The episode of The Office that dedicated to Entourage' and the "Let's hug it out, bitch" quote. On the same note, the Entourage episodes that date themselves by showing off old PS2 games the characters got into.
Any episode of Celebrity Deathmatch where the famous person was only relevant in the late 90's or the mid-2000's (ex: Natalie Imbruglia & The Real World cast members, or Mike Jones & Ashlee Simpson, etc). On top of that, childish toilet humor takes up more of the jokes than pop culture references, so you'd be more likely to see a celebrity shoving their hands down their pants to use their soiled hand or clothing as a weapon than seeing props from their movies/videos being used.
The Breaking Bad episode where Jesse happily plays Sonic 06.
The times where Chappelle Show would make fun of things from the 2000's like Lil Jon, Dubya, GTA 3, and Howard Dean's "BYAAH". Mencia's Lil Jon ripoff with the Sean Paul skit applies too.