A ball pit (originally called "ball crawl" also known as a ball pool or ball pond) is a pit,usually rectangular and padded,filled with small (generally no larger than a baseball) colorful hollow plastic balls.It is typically employed as a recreation and exercise for small children. Ball pits are often found at nurseries,carnivals,amusement parks,fun centers,fast-food restaurants. Ball pits may be rented for parties, and smaller versions are sold for use in the home. While ball pits are traditionally regarded as a children's plaything, some are large enough to accommodate adults.