This episode has leaked to the Internet one week before the actual airing.
The Day The Earth Looked Stupid was originally supposed to end with Kang and Kodos making a direct reference to the War in Iraq as they observe the ruined remains of 1938 Springfield. While the FOX censors had no objections over the line, the writers felt the reference was too obvious and had it cut to make the joke more subtle (though the leaked Internet version has the line that ended up being cut).
Moe: Whohoho look at that! My blood's a genius. Fancy Roman numerals and everything.
Marge: That almost torn my head off.
Homer: Oh, you always find an excuse not to make out.
Teen: Tell my friends I died kissing a girl.
Blob Homer: No!
Blob Homer: Must eat more fat people. Thank god I'm in America.
Mrs. Golem: Ouch. What's with this outfit? It looks like a lion ate a parrot and then threw up. (laughs)
Krabappel: Settle down children. Have a cigarette to calm your nerves.
Kodos: Colonel Kang, your report.
Kang: Ouch, well, the earthlings continue to resent our presence. (An explosion outside) You said we'd be greeted as liberators!
Kodos: Don't worry. We still have the people's hearts and minds. (He holds up a heart and a brain)
Kang: I don't know, I'm starting to think operation Enduring Occupation was a bad idea.
Kodos: We had to invade. They were working on weapons of mass-disintegration.
Kang: Sure they were!