Castle fans, get on the case: For the first time in TV Guide Magazine's 57-year history, they are letting TV fans choose the cover. At this link you can vote from among six fan favorites and the winner will appear on the cover of the December 13 TV Guide. The options are Bones, Castle, Chuck, How I Met Your Mother, Smallville, and Supernatural. The other shows all have strong fan bases, so Castle lovers need to step in and shut the front door on 'em. You can vote as many times as you want. The poll is open until November 1. Go forth and vote!