One of my earliest memories is playing Transylvania late into the night (er, early evening, since I was probably 7 at the time). The game is ludicrous (goblins, aliens, vampires, werewolves, etc) but somehow remarkably enjoyable. This is one of those games whose philosophy is "story? continuity? what's that?", with the end result being that you never know what surprise is coming next (okay, so you're supposed to rescue the princess Sabrina - I guess that is story, but most of the game has nothing to do with that). And what can beat the graphics drawn right in front of you as if a hyperactive child sits inside your monitor with a pen?
Note: I much prefer the Apple II version of this game to the ugly MS-DOS version, so I recommend that you search for that if you are interested in this game.