Last year, Aimee Mann released a pretty funny short movie about trying to get celebrity guests to join her for her annual Christmas show, and she's followed it this year with a four-part spoof of A Christmas Carol featuring John C. Reilly, John Krasinski, Paul F. Tompkins, and more. If you've got 20 minutes to spare, check it out. If you don't have a ton of time, definitely watch part three, in which she negotiates with Michael Cera. The whole thing was directed by Tim Heidecker of Awesome Show, and he makes an appearance as well.
Here's last year's movie (22 minutes) in case you have lots of free time; it features Patton Oswalt, John Krasinski, Paul F. Tompkins, and lots more.