A tool used to procrastinate. It is an application on Facebook that serves the same purpose as minesweeper, solitaire, freecell, hearts, and that pinball machine game. Again, there is no other reason for it's existence but procrastination. It was actually created because some lazy programmers were procrastinating making a more useful application.
Zack: Did you study for the quiz today?
Brad: Nah, man, I couldn't stop playing Jetman. I was gonna study, but I had to beat my record. Plus I had a few challenges to finish.