I have two faves:

1) 'It's a BIG ad! Really big ad!' Good old Bundy =]

and 2) the Pura Light Start milk ad, with Akmal Saleh (or however you spell it) and he's making facial hair with his milk, and he makes a beard and goes 'Who's this? IT'S YA MUM!' and I CRACK up laughing every single time.

Bloody hilarious.