The numerous jokes about the bat wings on the warriors' helmets. Squeak! Squeak!
Shout Out: The poisoned milk scene at the end is lifted from Alfred Hitchcock's film Suspicion.
There are numerous shout-outs to The Lord of the Rings, including the closing sketch where Servo attempts to forge a Ring of Power for Mike. Keep in mind this was several years before the movies came out.
Sick Episode: Pearl is suffering from ailment and making Clayton suffer along with her.
(The opening credits show "John Allen Nelson" in a faux-Old English font) Mike: John Allen Relson? Servo: "Nelson", it's "Nelson". Mike: That's one of the most clearly written "R"s I've ever seen! (And Deathstalker gets called "Relson" through the rest of the experiment.)
Take That: The host segments really take apart RenFests.