Garfield is a pretty funny comic in it's own right. But what happens when you start tweaking it a little? Here are some sites that have monkeyed with the strip and ended up with (what I consider) hilarious results.
De-Garfed The premise for these altered strips is fairly simple...just delete Garfield's thought bubbles to make John look like a raving, schizophrenic loony:
Garfield Minus Garfield This project takes the premise a step further - removing Garfield altogether:
Realfield My favorite of the Garfield variants. In Realfield, Garfield is replaced with a more lifelike, albeit mute orange housecat. Realfield doesn't talk, think or express emotion, yet he manages to do what all cats are best at - making their owners feel like morons.