Going surfing? Priceline says take a Camaro

Priceline's costly reservation

Summer travelers heading out for extended weekends have a new way to get to the beach when booking on Sports cars. As the largest online travel agent, Priceline Group gets the vast majority of its revenue from hotel bookings. The company is trying to juice up its car rental business with a new offering called Fun Rides.

It's no longer just economy, mid-size or full-size cars. Want to speed down to Santa Monica and take in the sun? Try a Chevy Camaro convertible. Going on a high-class camping trip in Yellowstone National Park? Check out an Infiniti Crossover. And if you need to fit into those tiny Manhattan parking spots, there's the Mini Cooper.

"We're seeing sports cars are really what people tend to be booking right now," said Bill Jose, senior vice president of the rental car business at the Norwalk, Connecticut-based company. "We want to accommodate customer needs, whatever they may be."

Priceline has quietly been on a tear over the past decade, evolving from a site known for the name-your-own-price option on flights and pitchman William Shatner, to a $64 billion Internet behemoth that facilitated almost $40 billion in online bookings last year. About 85 percent of its business is outside of the U.S., driven by, its Amsterdam-based hotel reservation unit.

To diversify beyond accommodations, Priceline agreed last month to buy restaurant reservation service OpenTable for $2.6 billion. The company is also boosting investment in rental cars, its second biggest business (margins on airline bookings are notoriously thin). Automobile bookings increased 37 percent last year, slightly more than hotels.

Priceline buys OpenTable

Priceline buys OpenTable

Priceline introduced Fun Rides in June and said travelers can use the service to book cars at airports in 63 U.S. markets from providers including Avis, Budget and Hertz. Jose said that number is up to 110 markets and growing.

The next piece is to make Fun Rides bookings available on mobile devices and expand the business overseas, Jose said. And what's after that? Harley-Davidson fanatics get ready.

"Down the road we may offer things like motorcycles and more exotic cars," Jose said.

By CNBC's Ari Levy. Follow him on Twitter: @levynews