Last night at April’s New York Tech Meetup, Brooklyn-based Whistlebox showed off DoCrew, an online cartoon project for kids with a real-world twist. The site connects with your webcam to allow kids to engage with cartoon characters in active ways, and offers social gaming aspects as well.

Other startups allow the easy creation of cartoons. But DoCrew’s use of a webcam allows it to fuse the genre with augmented reality, an increasingly popular visualization tool that overlays virtual elements into a view of the real world.

DoCrew’s cartoon world is typical for a children’s property. The environments are colorful and woodland-based, and the wacky characters would be at home in your average kids cartoon show. What makes it different is the way kids interact with it. Instead of passively absorbing content while sitting on a couch, the site encourages kids to stand up and move around as much as possible.

DoCrew uses webcams to bring kids inside of the cartoon to make them part of the action. The active participation comes from the site’s effective implementation of webcam motion recognition, which allows kids to use their entire bodies to interact with the events on screen.

Whistlebox demonstrated several games: One involved helping the characters move mud pies across a river with your hands, while the cartoon characters counted off the amount you successfully moved. Another had the player jump to help one of the characters collect coins and avoid obstacles. There was also a dress-up portion of the site that allowed kids to decorate their webcam images with virtual props in real-time. The company also demonstrated a simple mouse-like interface using your fingers.

The site is currently free and aimed at kids ages three to seven. Whistlebox has plans to expand the content for other age groups as well. Judging by the excited reactions from the crowd last night, the technology is definitely something that people want to play with.

DoCrew is currently free, but it will be moving to a subscription-based model like Disney’s Club Penguin kids site. In addition to other child-oriented play sites, DoCrew also seems to be competing with the motion controls on Nintendo’s Wii, and upcoming motion offerings like Sony’s Move controller on the PlayStation 3, and Project Natal on the Xbox 360. The big difference is that you don’t need any special equipment aside from a webcam-equipped computer.

Aside from DoCrew, Whistlebox is known for its technology which allows website owners to create their own video portals. It powers Sugartube, a video site for the Sugarbush ski resort in Vermont.

Whistlebox previously raised $2.3 million in first-round funding led by King Street Capital.