Here's what rhymes with playground.

Consider these alternatives

gym / him amusement / movement recreation / relation kids / its bleachers / features rink / link classroom / bathroom recreational / educational patio / no pools / schools pool / tool park / dark swimming / beginning barbecues / whose amphitheater / theater volleyball / small playroom / dayroom cafeteria / criteria lawn / long pastime / halftime lounge / found overgrown / known biking / striking