It looks like tennis, but the court is half the size. The rackets aren't rackets, but more like giant ping-pong paddles. The ball isn't made of yellow-fuzzed rubber but a wiffly plastic, just like you used when you were a kid. What is it? Pickleball. The sport, which is offered at the John P. Thayer YMCA on 14th St. two days a week, is a combination of tennis, ping-pong and badminton. It's played with oversize paddles, a plastic ball and a low net. ADVERTISING inRead invented by Teads The court is small, about 44 feet by 20 feet compared to...