I dunno... Sixteen Candles is pretty cult-y. And a personal favorite cult flick is The Villain, featuring Ah-nuld, Ann-Margret, and Kirk Douglas. It was a comedy western, about Douglas trying a bunch of Wile E. Coyote type-tricks (like painting a tunnel on a cliff-face) to kidnap Ann-Marget. She kisses him at the end and he hops around like Daffy Duck.
They Live is a great movie... there's a scene in the middle where Roddy Piper and Keith David beat the shit out of each other for fifteen minutes, over David's refusal to wear alien-spotting sunglasses. Utterly hilarious, because every time you think they've had enough, they start up again.
Surf Nazis is a movie you're better off reading about than actually spending money on.
I fell in love with the title, and ended up disappointed. Much better movies from Troma include Sgt. Kabukiman- NYPD, Nuke 'Em High, and Terror Firmer (features Ron Jeremy, as a mangled incestuous child molester. In a cage, in his son's apartment. ).