Vulcans take improv classes to act "normal." They're a surprise onstage because they never play the straight man. Being that one degree off from their sincere personality is confusing, difficult, and psychologically troublesome. But they can take a pratfall with comedic timing analyzed to the millisecond.

... actually, improv comedy is a great way to demonstrate understanding of a culture. Vulcans would make analytic connections between subjects in a heartbeat, and with some training they'd be excellent lateral thinkers. The gap between that and comedy is understanding expectations and violating them in a way that safely builds and releases tension.

Vulcans could tell brick jokes separated by months. You would never get them with a shaggy-dog story. They might have absurd reaction times for comebacks, but it would be limited, because I don't think they'd handle wordplay. You'd never hear a Vulcan mutter "that's what she said" in a timely fashion.