The real sport (hockey): A bunch of guys strap finely-sharpened blades onto their shoes and skate around on frozen water, beating up anyone in the immediate vicinity. Occasionally, a player decides to hit a small puck into the opposing team's net for points.
The video game take: Not much different from actual hockey, truth be told, but in Mutant League Hockey, all the players are undead skeletons, robots, and trolls. With an even greater emphasis on violent encounters, it lets you actually kill off the other team's players, forcing them to send in replacements. Hazards litter the rink, members of the crowd throw molotov cocktails, demonic goalies explode when scored on, and a giant slug that's basically a Lovecraftian Zamboni resurfaces the ice between periods. You know, now that I think about it, this sounds totally rad.