George Clooney's character in “Up in the Air” had business travel down to a science; tightly-packed rolling suitcases, monotonous cocktail hours, and hotel after hotel after hotel.

What about breaking free of mundane hotel walls and staying in a castle on your next business trip? Or how about a tree house?

On Airbnb, corporate travelers and couch-surfers alike are finding unique, reasonably-priced places to lay their head while on vacation or away on business. 

Andrew McCallister, business developmer for Heyzap, said the company has used Airbnb to book lodging for nearly 20 business trips in the past two years. After hearing good things from employees who used the site for personal travel, the San Francisco-based tech company decided to try it out on their next business trip.

At a conference in Seattle last year, McCallister said Heyzap employees stayed in a block of apartments right in the center of the city for around $120 nightly—a price they couldn't find at any major hotels.

"A four-star hotel is a four-star hotel no matter where you are," he said, adding that staying in an atypical location on business travel is a great way to spice up the trip. "The fact that you can look [online] beforehand at all of these amazing photographs of these homes before you get there gives you something to look forward to."

The most unconventional location Heyzap employees stayed at was a "quirky" apartment in New York City, with amazing views of the skyline, McCallister said.

Christopher Lukezic, lead marketing manager for Airbnb, said the company's transition to business travel happened naturally through word of mouth. Bored business travelers looking for something different or more "home-y" opt to book their trips through the company rather than typical hotels, he said.

"It’s a great solution when you are in a city on assignment for three or four weeks," Lukezic said.

Lukezic said Airbnb is popular among entrepreneurs and startups with small travel budgets looking for deals. He also said folks in creative fields like design, architecture, art and photography have also become loyal customers.

Travelers have a plethora of lodging venues to choose from including Airstream vans, traditional teepees and castles all over the globe.

Currently, Airbnb has nearly 50,000 active listings which are turned on and off based on availability. Since the company start in 2008, there have been more than 80,000 listings in 176 countries. In 2010, it booked more than 700,000 nights for travelers.

The company currently has 45 employees, and Lukezic said it is growing fast, adding about one employee per week—a true feat in this economy.

Typically, companies give workers on extended business trips to book the venue of their choice, price-permitting, he said.

"Companies give workers the option [to book where they want] because they want them to be comfortable," Lukezic said. "Internationally is where we have seen the most growth for business travel."

Staying in an out-of-the-box location gives a traveler more of a local experience, no matter the location, Lukezic said.

"If you stay in a hotel district, you may not have as unique an experience as you would in a neighborhood," he said. "Business travelers are fortunate; they get to go all over the world and can have a local experience even when they are on assignment."

It's also a great conversation starter for business travelers, said McCallister.

"It's an amazing discussion starter when someone on a trip asks 'Where are you staying?' and you say ' In a tree house," he said.

Follow Kate Rogers on Twitter at @KateRogersNews