Pretty self-explanatory. List the best and worst games you have (in your opinion, of course).

I'll just list them by console because I'm a doofus that likes listing things.
Famicom
Best: Raf World
Worst: Transformers: Convoy no Nazo (or Mystery of Comvoy as it says on the label)
Best on multicart: Raf World

Worst on multicart: Adventures of Rocky and Bullwinkle and Friends or Mario is Missing!
NES
Best: Duck Tales
Worst Duck Tales

Game Boy
Best: Tetris
Worst: Alleyway
Best on multicart: Contra: The Alien Wars
Worst on multicart: Digimon 3 Crystal and Digimon Pocket
Game Gear
Best: Sonic the Hedgehog
Worst: I don't have any "bad" games, but I'll say Outrun Europa because the screen flashes for no apparent reason
SNES
Best: Parodius
Worst: Mario is Missing!
PS1
Best: Rage Racer (although that might change if I can get the Bubble Bobble collection)
Worst: I'd say Atlantis the Lost Continent, but that doesn't really count as a game so I'll say Break Out instead
Game Boy Advance
Best: Mario Kart: Super Circuit
Worst: Monopoly
PS2
Best: Either Okami or Metal Slug 3
Worst: Sega Classics Collection
GameCube
Best: Super Smash Bros. Melee
Worst: Again I have no "bad" games for this console (although I only have 9 to begin with) so I'll just say Crash Bandicoot: The Wrath of Cortex
PC
Best: A toss-up between Theme Hospital and Doom
Worst: Most of the games on More Then 250 Games For Windows 95
Nintendo DS
Best: Contra 4 (imported of course, because Europeans apparently don't deserve good games)
Worst: 42 All-Time Classics