There was apparently some footage of McCain making a speech in front of a green screen that was aired on television recently. Stephen Colbert, genius, saw this as an opportunity to make the guy look silly and cause laughs everywhere.

His recent campaign on the show has been a challenge to viewers to come up with some kind of background for the green screen to make McCain look interesting and/or fun to watch. Results were often hilarious.

Here's the list:
http://www.colbertnation.com/?cat=24

Here's one of my favorites:
http://www.youtube.com/watch?v=JvnmvTzm_OU