Basically all of the Women and Women First/Feminist Bookstore sketches. Toni and Candace are just wonderfully passive-aggressive (and sometimes just full-on aggressive) to anyone who isn't them and have no business or people skills whatsoever. Watching regular people wander into the madness that is their store and then becoming desperate to escape it is never not funny.
The Lucky Seven Punk House skit, especially Fred's impression of a self-righteous punk.
"Look what the government dragged in. What's the matter? Congress got your tongue!"