Simple, fun and can generate huge traffic.  Jack in LA had fun doing this feature using mullets,, and the MLB, with XM, put together a bobble-head feature.  Granted, the "Elf/Scrooge Yourself" feature is a bit more encompassing, and can require some significant resources, but that very feature put Office Max, an otherwise staid web adjunct to a brick-and-mortar outlet, into the Top 10 Web sites in terms of traffic last December.  So, they would undoubtedly consider it to be worth the expense.  And don't forget the Simpsonize Me site, another great interactive/viral campaign along these lines.

Always require a sign-up to your database to participate - and be certain that the viral elements are in place (email/suggest to a friend-type feature).  Share the application with bloggers and message boards to get some organic growth as well.

These can be as simple as repurposing a "sign generator" and allowing uploads of photos or other material.  Dozens of open-source applications along these lines are readily available that could be repurposed quite easily.  Another option is to have listeners submit their photos and simply insert them into a template yourself (using Photoshop, Fireworks, Corel Draw, etc.)

This could be the easiest thing you do to to enhance your digital presence.  If your station - and EVERY jock doesn't have a MySpace, Facebook, or Twitter page yet... Get one!

As Leo Laporte (or TWIT.TV fame) said at Summit 13 this year - personalities without a MySpace, Facebook or Twitter page won't have a job in a year.  It takes minutes to set them up, and can attract hundreds (thousands?) of "friends" and followers in short order.  These sites provide multiple outlets for posting blogs, station events, pictures, videos, and other things that help pull the curtain back further and make your station more relatable - and interesting - to your audience.

While these efforts do vary in their overall importance depending on your demo target and format, we are seeing more and more "older folks" use these site (40-55 year olds are moving to Facebook in droves).