Best bets on TV tonight

“How I Met Your Mother” (8 p.m., CBS): On “How I Met Your Mother,” it’s time for another round of “Slapsgiving” action, and you know what that means: Barney better brace his face for pain.

“Castle” (10 p.m., ABC): Uh-oh. We’ve got a tricky situation brewing on “Castle.” When a man’s body is discovered in a garbage chute, two women step forward to identify him: his wife and his fianc e.