There are a lot of ways to build fast-growth companies. Just consider this year's Inc. 5000 list. The annual ranking of the fastest-growing private companies in America includes everything from canned wine producers and freight movers to kayak makers and truck bumper manufacturers.

The six companies below, though, take the cake when it comes to innovative business models. Whether it's reinventing hospital garb or hosting mind-blowing vacations, these startups all have one thing in common: They've tapped into something their customers really  wanted. 

Here are the most innovative business models of this year's Inc. 5000, in no particular order:

1. Renegade museum tours.

Museum Hack, No. 1,304 on this year's list, is built on a counterintuitive premise: The startup sells "museum tours for people who don't like museums." For one price, customers get museum admission, a several-hour tour, and in some cases, wine. Guides teach them about the displays but with an element of snark: maybe an examination of just how safe that blue whale display really is, or a dive into the artist's weird hobbies. Some tours are family-friendly while others are adults-only. The company pulled in $2.7 million in revenue last year. Tours are available inside New York's Museum of Natural History and the Art Institute of Chicago, among others. "Museums aren't competing with other museums," founder Nick Gray told the The New York Times earlier this year. "They're competing with Netflix, Facebook and iPhones."

2. Comparison shopping for surgeries.

MDSave's website lets you shop for medical procedures the way you'd look for rental cars or hotels. The startup, which bills itself as "the world's first transactional health care marketplace," gives users a way to compare doctors' prices within a designated location. Additional fees, like bloodwork or biopsies, are included in the cost, so customers don't get caught off guard later. Launched in 2013, the startup booked $15.5 million in revenue last year and earned spot No. 152 on this year's list.

3. A makeover for medical uniforms.

Figs co-founders Trina Spear and Heather Hasson took an overlooked item--medical scrubs--and turned it into a lucrative business. One of the first e-commerce companies to sell scrubs directly to consumers, Figs reimagines what hospital garb should look like. Gone are oversize and boxy uniforms: The startup makes slimmer, gender-specific outfits made of smarter materials and with features like pockets for wedding rings. The company caught the attention of Will Smith and former Lululemon CEO Christine Day, both of whom are investors. Figs, which earned $23.1 million in revenue in 2017 and expects to top $100 million this year, ranked No. 22 on this year's list. 

4. Like Jurassic Park, but with exotic animals.

After selling his startup HostGator for $220 million, founder Brent Oxley decided to build an 18,000-acre ranch in the heart of Texas. He imported animals--some from zoos, and some endangered--from all over the globe and constructed a 6,000-square-foot lodge, a private runway, cabins, and a high-end restaurant for his business. Visitors to the Ox Ranch can stay among kangaroos, giraffes, elk, and wildebeest. The model isn't without controversy, though: Guests can pay up to $35,000 for the right to hunt certain species. The ranch pulled in $6.2 million in 2017 and finished No. 246 on the Inc. 5000.

5. Brand crowdsourcing.

You've got the business idea. Now you just need a creative and memorable name. SquadHelp blasts out your proposal to its network of thousands of creative and branding types, who then submit their suggestions. The company automatically checks each for URL availability. You choose the winner, and its submitter gets paid. SquadHelp then performs trademark risk assessment, linguistics analysis, and audience testing. A campaign starts at $199, and the company says you'll typically receive dozens or hundreds of responses. SquadHelp reached No. 247 on this year's Inc. 5000, generating $2.5 million in revenue in 2017.

6. Housing help.

Most 19-year-olds don't know much about real estate. Rent College Pads, No. 514 on this year's list, gives college kids a place where they can search for off-campus apartments specifically geared toward students. Landlords can list their properties directly on the site and students can send them questions, making the process more efficient and less expensive by cutting out the middleman. Rent College Pads, which launched in 2015 and is available near universities like Penn State, Cornell, and Texas A&M, hit $2.8 million in revenue last year.