Is there a point at which excessive, public self-humiliation becomes its own form of warped narcissism? Much of Will Ferrell’s comedy revolves around the clueless preening of his hairy, doughy characters, including Jackie Moon, the minor-league basketball player and owner of Semi-Pro. This time around, though, the joking at his own expense feels a bit self-indulgent, simply because there isn’t much else to the picture. Semi-Pro follows a fairly conventional sports-movie trajectory, allowing for little of the improvisation at which Ferrell excels.