The scene at Duke's. Shotguns akimbo and they managed to make "Shabbat shalom" badass.
To elaborate: based on a false tip, Mordechai goes into a Neo-Nazi bar. After he figures this out, he pulls out two shotguns and declares "Shabbat shalom, motherfuckers!" Cut to outside, where he pours alcohol on the ground then lights it, creating a burning Star of David.
It should be noted that Adam Goldberg was reading the script and got to the line he's supposed yell "Shabbat shalom, motherfucker!" and decided right then and there that he wanted to star in this film just so he could say this line.