Justin Kan has made a career out of taking slightly bizarre behaviors and turning then into tech start-ups. Four years ago, Kan attached a camera to his head and started broadcasting every minute of his life. Amazingly, not only did people tune in as Kan watched TV, went on dates, and (yes) went to the bathroom, but the odd experiment in "lifecasting" turned into a real business. Today, Justin.tv has 60 employees and is one of the most-heavily trafficked live-video sites on the Internet.

Late last year, Kan stepped away from his eponymous company to focus on a new business: A start-up that enables people to use their smart phones to find random strangers to perform tasks.

Exec, which launches today in the iPhone app store, works like a virtual temp service. Users log on, post their job—say, deliver flowers or take their dog for a walk—and are paired with their own personal gal (or guy) Friday in a matter of minutes. Kan founded the company with his brother Daniel, who ran sales and business development at UserVoice, and Amir Ghazvinian, who mastered in Bioinformatics at Stanford. For the past few months, the three men have been incubating the company in Y Combinator, the Palo Alto start-up boot camp, where Kan also serves as a partner.

Unlike TaskRabbit, a website that allows part-time workers to bid on a given job before they're hired, Exec automatically pairs a task-creator up with a (pre-screened) assistant. It charges a flat rate of $25 per hour, no matter the task.

"Our system is set up for emergencies," says Kan. "We're taking away all the mental work involved in hiring someone."

So far, all of the company's 30 part-time workers, which it calls "execs," are in San Francisco, but the plan is to eventually expand to other cities.

The idea had its genesis last year when Kan and a couple of buddies were driving from San Francisco to northern Nevada for the Burning Man festival and realized that they'd left a ticket back home. Rather than turn the car around, Kan fired up Uber—a service that lets you quickly order a car service using your iPhone—and hired a limo driver. The driver got the ticket, dropped it off with another friend who hadn't yet left for the festival, and disaster was averted.

"I thought, 'There should be an app for this,'" Kan says.