Letters to Santa, the Second City's annual 24-hour improv and music charity show, begins Monday, Nov. 23 at 6pm at Second City's e.t.c. Theater. If you're lucky enough to get through the door (tickets are $20 cash, limit two), you'll see performances by alumni including TJ Jagodowski, Kate James, Horatio Sanz and Fred Armison, and musical guests Jeff Tweedy, Kim and Kelley Deal with Carrie Bradley, AC Newman and Bonny Prince Billy, among many others. The show will be streamed live on the web, and there's also an online and in-person auction for such items as a living room concert by Jeff Tweedy, meetings with Cecily Strong and Aidy Bryant and two tickets to "SNL," and one-on-one startup advice from Groupon founder Andrew Mason.