Super old school contributions:
The last night Pound (John Bowie, Seth Morris, Rob Corddry, Brian Huskey, Ari Voukydis, and Colton Dunn that night, I think - while Dyna Moe and Will Berson were on the team also) played Harold Night before people went all Hollywood, I used Los Fabulosos Cadillacs' "El Matador," which wound up being an awesome intro.
For their "Good Vs. Elvis" midnight show, Respecto used "A Little Less Conversation" by Elvis as an intro. I would clear the house with "Jesus On A Greyhound" by Shelby Lynne.