Tonight’s late-night Saturday Night Live, at 11:30 p.m. ET, is a repeat of this season’s opener – but the prime-time SNL repeat is of a much older vintage. It’s from 2000, and is one of the episodes hosted by Christopher Walken, with Christina Aguilera in her post-Disney, pre-Voice period. Primary reason to watch? Two words, repeated many times by Walken in one instant classic of a skit: “More cowbell!”