S.F.-based zozi might be worth checking out the next time you want to challenge yourself by pushing the boundaries of your comfort zone.

The startup offers experiences like hang-gliding, mountain biking, or abalone diving.There are also more prosaic options, like tennis, golf or cooking lessons.

“We are the go-to place for high-quality experiences,” says founder and CEO T.J. Sassani, whose inspiration for the company came when he encountered bull sharks while diving in Australia a few years back.

“At that moment, I suddenly realized there was nothing to fear – the sharks couldn’t care less about me – and I decided to try and make these kinds of experiences easier for other people to have.”

Today, zozi, which partners up with the merchants who provide kayaking, biking, diving and other adventures in 25 cities across North America, is “closing in on a million customers over the next few months,” Sassani says.

Launched in the city originally as ekoVenture, the company initially focused on multi-day trips, before repositioning itself around what Sassani calls “bite-sized adventures,” which are usually one day or less and available to individuals as well as groups.

Most of zozi’s transactions are conducted through email, although the company is integrating more tightly with social media platforms as well. Customers can earn discounts by sharing experiences with friends.

Gifting also accounts for a portion of its bookings.

The company makes money via revenue shares with its partners, andits open API is embedded in “hundreds of sites and products,” according to Sassani.

“We’ve doubled our revenue run rate the past three months,” he says, “and our staff currently numbers 47 people.”

The business tends to be seasonal, with a dip in summer (“when people are on vacation”), picking up again in September and January.

“San Francisco is the market where we earn the most money per subscriber,” says Sassani.“This is a very zozi city – people tend to be very active and experiential here. Also, the quality of activities here through our partners is very high.”

In May the company closed a $7 million Series B round of funding from a group of investors, including David Tisch, LaunchCapital, the Pritzker/Vlock Family Office, ZIG Capital, Thomas & Peter Lehrman, and 500Startups.