Spikeball is a trendy, fast-paced game that combines elements of volleyball and four square. Instead of hitting a large ball over a straight net, your tween will be smacking a softer, grapefruit-size ball onto a bouncy, ringed net, sort of like tetherball but without the string. Be prepared, parents: This is a physical game that requires fast movement and probably some diving to score points. Consequently, this might be best for just the kids, though it does require four players.