I remember playing this game ages ago, when I was 5 or 6 years old, with my sister.
It's just a game about volleyball. Players (the game can be played PC vs PC, You vs PC, You vs Another-You), control some kind of big head that can jump and can make the bounce the ball on their heads. You all should try it, with another person next to you to play with, of course, it's lots of fun.
I don't know whats the policy in these forums about abandonware and that kind of things, so I won't post a link to download the original game.
Although, I will post a link to a remake
GPL Arcade Volleyball
(I haven't tested the remake, I'll do it once I get home).
Enjoy it!