Keepers

Here there be monsters.  Also, over there there be monsters.  There sure are a lot of monsters about.  Be a Keeper and try to capture the monsters, use their skills, and out-roll your opponents.  The first keeper to capture one of each type of monster will win.  I'm not saying you've got to catch them all, because that sounds copyrighted, but catch a variety of them.  

The game requires a d20, a d10, a d4 (found in a standard set of polyhedral dice), and a pencil.  For 2-4 players of all ages.