Look at all that AJAX! This site is really TDO.
Tactical Day Off: when somebody takes a day off school/college in order to catch up on work, or avoid a deadline. Not to be confused with bunking, which is done simply for amusement/lack of motivation.
Teacher: Where is Bloggs? 'Ill', again?
Class: TDO, sir.
Bloggs: I do IB; TDO's have become a necessary part of my schedule.