I had nearly forgotten my extreme fondness for Mad Libs, which was cultivated during field tips in my early childhood, and then calamari [1] alerted me to the fact that you can play them online!
In case you missed out, Mad Libs is a word game where one player prompts another for a list of words to substitute for blanks in a story, what results is a hilarious, and often nonsensical, story that is best read aloud.
If you want to play online there's an official site with three options [2] and a non-official site [3], which is user generated and has 155 to choose. Both are hilarious, geeky and another great way to waste a couple of hours at the office.
To quote calamari: This is awesome, I'm totally 9 years old again.