Two And A Half Men (2003) - 3x23 - Arguments for the Quickie

Charlie's ex-girlfriend, Mia, comes back in town with an unexpected request, which Charlie follows with an unexpected question of his own.

When Charlie finds out that Mia is in town with her dance troupe and has invited him to her performance, he opts not to go and tries to convince Alan (and himself) that he's over her. After surprising Alan (and himself) by showing up, Charlie gets another surprise when Mia explains that she wants something personal from him -- his sperm. Shockingly, commitment-phobic Charlie responds by asking Mia for something as well.