When Hank comes home from the vasectomy, Becca is trying to play Slayer's "Raining Blood" in the Guitar Hero video game. In season 1, all the books Hank had written were named after albums by Slayer.
During Hank's vasectomy the nurse is played by Sheri Moon Zombie wife of Rob Zombie. Later on the song (Go to) California is played, sung by Rob Zombie.
The guy who makes out with Mia at the party is played by Pete Wentz.
At the game over screen in guitar hero, it shows 39% completion the first time, but for the rest of the scene it only has 36%