This one has Lisa Simpson's face. It says "See You Real Soon Kids," which was Krusty the Clown's epitaph in "Bart the Fink," in which Krusty fakes his own death to avoid being prosecuted for tax evasion.
This one has the face of Tessek, Jabba the Hutt's Quarren accountant. It says, "Cthulhu Fhtagn," which means "Smile! Cthulhu loves you!" (or "Cthulhu Dreams," depending on which translation of The Necronomicon you read.)
This one has a face from a creepy Christmas decoration. It says, "War is Sexy. War is Fun." This comes from the Dead Kennedys song "Rambozo the Clown."
This one has a Wampa face and says "Jesus Was a Terrorist," from the Jello Biafra song of the same name.
This one was created to try out a new eyeball mold.