It took a couple of viewings for me to get the pun for Grenadier and "Dark Chest of Wonders". Flat out stating it like that makes it obvious, however.
Also, the Dragonball Z clip with Boondocks audio. It took me the longest time to get why Goku's line of "You cannot force me to be someone I'm not" was supposed to be funny...until I realized the one saying "the hell I can't!" was Captain Ginyu.