This year for Christmas the boys got a "Giga Ball" from their Grandma and Grandpa Greene. It is a giant inflatable ball, about 51" in diameter, that has an empty cavity in the center where one child can get inside and be pushed and rolled around. Since the package says that it will hold up to 150 lbs, I went ahead and took a turn. It is so much fun! The boys and I could do this for hours. We have some friends who received an 81" ball for Christmas so I'm anxious to try theirs out.The Giga Ball-it's like living all those childhood dreams of joining "the carnies" in the circus! Fun stuff!