Mick Mountz is a caffeine junkie. On any given day, he downs three or four cups of coffee and a few cans of Mountain Dew. Perhaps Mountz, founder of Kiva Systems, is trying to keep up with his company's indefatigable orange robots, which are rapidly replacing conveyor belts and carousels at the order fulfillment warehouses of retailers such as Zappos, Staples, and Diapers.com (No. 35 on our list). An MIT engineering whiz who got his start at Motorola and Apple, Mountz, 44, spends his days bouncing around Kiva's headquarters in Woburn, Massachusetts, diagramming algorithms and showing off the robots to prospective clients.

I get up at 5:30 or 6 in the morning, go right downstairs, and grab a bowl of cereal. Sometimes it's healthy, sometimes it's not. Lately, it's been Lucky Charms. I wake up with the morning news while I eat. I try to catch the Red Sox score and get a quick dose of the weather. Then I go turn on the coffeemaker.

I head upstairs to my office and get my laptop to see if there are any e-mails I need to respond to quickly. I don't do the BlackBerry. If I'm going to send an e-mail, I want to sit down at a keyboard. I have an iPhone, but I mostly use it to show videos. When I'm at an event, inevitably I'll be explaining our product to someone and the person will say, "I don't understand. Do the robots pick up the products?" I'll say, "No, the robots pick up the shelves." Then I'll show the person a video of the robots in action.

After I check my e-mail in the morning, I'll take a glance at my calendar to remind myself of the key things happening that day. If I have customers coming in, I'll say, "I gotta shave today." Sometimes I have a five-shaver week, and sometimes I have a one-shaver week -- those are my favorite. When I'm in the shower, I'm mentally prepping for the day. Sometimes I get so distracted, I wash my hair twice.

Once I get dressed, I grab my laptop, make a cup of coffee to go, and bolt out the door. It takes 15 minutes to drive to the office from my house in Lexington. On the way, I turn on sports radio and listen to the guys complain about the Sox. I played baseball for four years at MIT, and I'm still a fanatic. I would love to watch a Red Sox game every day if I could, but I usually just catch the box scores.

I wear jeans to work every day. Our rule here is that you can wear whatever kind of clothes make you the most productive. I'm more comfortable in jeans, therefore more productive. We have the same rule for computers. I use a MacBook, the finance team uses PCs with Windows, and the engineers use Linux on both Macs and PCs.

Mornings are a good time to get a two- to three-hour block of serious work done. By 7 a.m., I'm usually in my office and ready for another cup of coffee. I turn on my laptop and check my e-mail again. If I need to get something done for a client meeting later in the day, I'll close the door, which is the sign that I'm trying to crank out a presentation.

During the day, I usually have a handful of scheduled meetings -- there might be a design review for a new customer's system or something related to manufacturing, finance, or the account pipeline.

I keep my own calendar. It's one of those weird things: How do you describe to other people how to prioritize and manage your time? I've been using iCal, Apple's calendar tool, ever since I started the company, so it serves as a kind of history. If I do a search for Gap, the application will tell me every meeting I've had with Gap since 2003. I add everything to my calendar and prioritize on the fly.

Throughout the day I use a lot of visuals. If we're talking about a design for a pod -- the shelves that store inventory -- it's easier to look at a sketch or a picture. Whenever we have a hallway conversation, someone will get a marker and do a quick drawing on one of the whiteboards lining the walls. At management meetings, I draw timelines on the whiteboard to reinforce a sense of urgency about deadlines and encourage coordination between different departments. When I go into the field, I take lots of pictures with my camera so I can show them to my team back at the office. Showing a picture of a fulfillment worker who can't reach a packing-slip printer is better than saying, "The printer is too high." With a simple photo in an e-mail, I can convey the issue to the mechanical design and deployment teams so they can lower the height of the printer shelf and make it easier for the operator to slide packing slips into cartons, with a simple flick of the wrist. When I show a picture, all of a sudden I get comprehension and action.

If I have a half-hour in between meetings, I could try to sit down in my office and do something serious. But I have an open-door policy in the afternoon, so chances are, I'll get interrupted a bunch of times. Instead, after I scan my e-mail and fire off one or two replies, I fill in the white space on my calendar by Ping-Ponging around the office, catching up with people. I may grab a Mountain Dew, go into the engineering office, and ask, "Any breakthroughs today?" I use that phrase instead of "How's it going?" to give the engineers a chance to talk about a tough problem they've been working on and how they solved it. They may be working on a better approach to queuing pods for the pick operators, for example, or trying to get a faster rotation speed during robot lifting motions. If they're having trouble with something, we'll get on the whiteboard. I do that every day, probably two or three times. I enjoy it, because it gives me time with the product. It also gives me a chance to interact with some of my college fraternity brothers who work here.

In the early days, part of my walking-around time would include grabbing someone and having a game of Ping-Pong while we talked about the new order-fetch algorithm. It was a great way to blow off steam. That's harder to do now, because I just don't seem to have 15 minutes to spare. But I still think it's important to have fun with the people you work with for 10 to 16 hours a day. At Kiva, people play basketball out back, do yoga on the mezzanine in the warehouse once a week, and have cookouts some Fridays during the summer.

I'm very hands on. If we have a new piece of hardware, I'll go down and review it with the product team on the floor. If it's new software, we'll whiteboard out any issues. In those conversations, I'm acting as a sounding board and challenging the team to think outside the box. Throughout the day, designers working on projects for various customers will sometimes pop into my office and say, "Hey, I'm working on this project, and I can't figure something out." I'll get on the whiteboard and coach them, or we'll go down to the floor to look at the pods or the robots.

My favorite part of the day is meeting with prospective clients. I'll take them through the whole demo system on the warehouse floor. They get to choose three different grocery items at random on our sample website and hit the Submit Order button. As three pods roll up to the station just a few seconds later, their eyes light up and they smile. It's that "aha" moment of realization that they would now have access to any product, anytime, anywhere in their facilities. Then I'll take them through a slide presentation, explaining how Kiva could solve their problems and answering their questions. When light bulbs start going off and they start explaining how we can help them, it's a fun moment.

If we have a client in during lunchtime, I may get a quick sandwich. But I usually skip lunch. I have a lot of caffeine during the day. I drink Mountain Dew because it's the most caffeine you can get in a soda. Caffeine is a stimulus for the mind. I tried going without it for a year, but I only lasted six months because I couldn't concentrate.

My schedule doesn't allow for physical fitness like it used to. When I lived on the West Coast, I did yoga and competed in triathlons. I still put workouts on my calendar, but they get stomped by meetings all the time. My advice to aspiring entrepreneurs would be to get in the best physical shape possible before starting a business.

I travel around the country to visit clients two or three days every other week. When I visit a customer site, I want to test the system. I visited Diapers.com recently and spent two hours filling orders for diapers and rattles. Some people might look at me and think, Gosh, I can't believe the CEO is picking orders in a factory. Doesn't he have people to do that? I believe good leadership is not only about delegating but also about getting down in the weeds. I also do it because it's a fun product, and I like using it.

I still put in long days, but I haven't been spending as much time at the office since my daughter, Katie Mae, was born a year ago. Instead of staying until 10 or 11 p.m., I try to peel out around 5:30 or 6, in the hopes of catching Katie Mae before she goes to bed. If it's after 6 and I know I'm going to miss her, that's not a good feeling. When I do get to see her, I get in a little bit of playtime, or maybe give her a bath. If she's still eating, I'll help feed her a bit.

After Katie Mae goes to bed at 7, my wife, Tiffany, and I sit down on the couch, watch the national news on TiVo, and eat dinner. We just moved into a new house, so sometimes after dinner I'll work with Tiff on a project, like hanging curtain rods in the living room. On Monday nights, we try to watch a really funny nerd show called The Big Bang Theory. It's about Caltech physicists. My wife likes to point out how their apartment looks like the place where I lived when we met in 2004, when I set up shop in Woburn. She'll say, "Hey, look! They have a whiteboard in their living room like you did!"

When you have your own business, your day is no longer your own. When I'm in my office, my time belongs to everyone else there. So every night until about midnight, I'm working on big-picture stuff. I may be looking at how our teams are lining up, thinking about an agenda for an off-site meeting, or working on our customer engagement process. Those are the kinds of things you need to do on your own time.

I can't just get in bed and fall asleep. I have to have something to distract my mind. So around midnight, I'll put my Mac on the nightstand and lie there and watch a documentary from my Netflix queue. It's usually something historical, about Alexander the Great or the lost pyramids of Egypt. I watched one about the history of the Dark Ages for, like, 10 nights in a row. What's funny is I only get to see five or 10 minutes before falling asleep. Then my Mac goes to sleep. The next night, I just rewind a little bit and pick up where I left off.