Secret Santa

A Secret Santa is a holiday tradition, with different names in numerous countries. In it, there's a system of secret picks, where a group of people pick names of someone else in the group and give each other gifts without saying who it came from.

It's often played straight, but there have been a number of times where someone sneaks their name in as the only one for the group. Hilarity Ensues. May result in one or more characters engaging in Convenience Store Gift Shopping.

In some cases this is called something more politically correct such as "Holiday Helper", since Santa is associated with Christmas and the people running the exchange don't want to appear to be excluding non-Christians. Another common Christmas-affiliated name for it is "Kris Kringle"; while this is another name for Santa Claus, if it's used it's normally in the context of a Secret Santa arrangement.

Examples of Secret Santa include:

Live-Action TV

Done in House, where he slips his name as the only one to mess with his team. They figure it out quickly, but he ends up getting gifts from all of them anyways.
In The Suite Life of Zack and Cody, Maddie organizes the Tipton staff Secret Santa and makes sure that London picks her name, hoping for an expensive gift.
Monk had an episode called "Mr. Monk and the Secret Santa". Stottlemeyer forgets to buy a gift for his Secret Santa, so he regifts a bottle of port someone had sent him. Then the bottle turns out to be poisoned...
Happens in a Christmas episode of The Office.
- And again, though not as a major plot point.
Happens in season four of Friends. By the end of the episode, pretty much everyone knows who got who.
In Glee, Sue slips her name in as the only one.
The Baby Sitters Club has the club play this in one TV episode. At one point they all go to the same store.

Western Animation

A Christmas Special of Hey Arnold! uses this as the basis for his difficulty in finding a gift.
This is a plot point in an episode of Braceface. Sharon pulls Nina's name, and is morally torn between buying her a nice present and not buying her anything at all.

Web Comics

Organized by DiV, of all people/electronics, in Penny Arcade...except that the only name in the hat is DiV.