Give a LinkedIn recommendation. See what I'm talking about? You won't want to write a recommendation and send it to someone with the note, "Merry Christmas," but a recommendation is welcome any timer of year, so why not do it now?
Retweet or promote a blog. Do you have a platform from which you can help promote a colleague's online presence? Are such promotions valuable? You bet they are. So in the spirit of giving and sharing, lend some promotion.
Provide some training. Are you the guy that knows how to bulk edit the TPS report or run a sales force query for archived date ranges? Then schedule a brown bag for one of the slow days around the holidays and teach everyone your skill.