Ah, yes, I'm familiar with that one.
Well, I hate to answer my own question, but I figure I'll just rattle off all the ones I'm familiar with:
-Garfield Randomizer(s)
-Garkov (I need a few more brain cells to "get" Markov in the first place)
-Garfield Minus Garfield (and other, similar site, removing thought bubbles, etc.)
-"Arbuckle"
EDIT: Fixed up the list a little, mostly for my own reference.