If you see people hitting a Wiffle-type plastic ball over a low (34"-high) net on a badminton-size court with larger Ping-Pong-style paddles, that’s pickleball.

Played as singles or doubles, pickleball—invented in 1965 by former Washington State Congressman Joel Pritchard and two friends—is a mashup of Ping-Pong and tennis.

“The constant action is a lot like Ping-Pong—there’s very little time between points,” says Rocky Clark, of Portland, ME, a regional director for the U.S.A. Pickleball Association. “And the footwork and court positioning are as important as in tennis.”

You serve the ball underhand and score a point when your opponent faults (fails to return ball, hits the ball out-of-bounds). The winner is the first to get 11 points.

Not surprisingly, it’s great exercise: A 150-lb person can burn about 360 calories in 30 minutes of aggressive playing.

Allegedly named after Pritchard’s dog, Pickles, the sport is cheap—as little as $8 for several hours. And, Clark says, with “drop in” scheduling—you can just show up and start playing—finding a game is easy.

For more rules and to locate one of the 4,000 courts, check out usapa.org.