GBA games you can play forever?

I want a GBA/GBC/GB game that I can play forever, since I'll probably never buy another. All I have right now is Pokemon and Advance Wars - both of which have somewhat of an unlimited replayability.

There is also Harvest Moon, but it seems to be sold out everywhere. Puzzle games that become stale after a day not wanted.

Thanks.

>>11
Don't tell him, the dumb fag would probably misinterperet it's hardcore rpg aspect (the most hardcore of any game btw) as puzzle.