Whether you're a hip hop fan, or not; practicing rapping off the top of your head will help you become more fluent in repartee. It's the next best thing after improv -

You're forced to make creative connections using metaphors and similes.

When a girl says something that makes your ears perk up you'll be able to make an intelligent connection to something humorous and jocular.

Throw on any beat. The ones that are the most fun are from Izak beats on YouTube.