Rock Hockey is an extreme Fraggle sport introduced in "Playing Till It Hurts."
The sport as it is known today was pioneered by Rock Hockey Hannah, who, according to Red, "practically invented rock hockey."
While definitely a Fraggle sport, rock hockey contains elements of several silly creature sports as well: ice hockey, basketball, baseball and American football. Each team consists of five players: two forwards, a quarterback, a first base player, and a goalie. Equipment used in the game includes a set of plaid hockey pillows (kept in good playing condition with pillow wax), long-handled nets for the goalie, and long-handled paddles for the other players. The standard uniform includes greaseberry leaf skates, helmets and seashell shoulder guards, and the goalie also wears a wicker face mask and long gauntlets.
The game begins with the pillows being batted off of the referee's head. The only discernible rule in rock hockey is that no player may exhibit unnecessary seriousness, the penalty for which is having the other players chant "naughty, naughty" at the offender.
The sport may or may not be related to pie hockey, mentioned in "Change of Address."