An extreme variety of multitasking, othertasking is the act of totally ignoring a present, serious task for another, usually less serious, task. Such behavior is only true othertasking if it is couched in the fiction that both tasks are being worked on.
"I really needed to watch the last half hour of that movie, but I was stuck in class, so I turned on my computer, put my earphones in and othertasked the movie. Way more efficient than just skipping class."
"There is no way I can write this essay and finish this crossword in the next hour... that is, unless I sit in front of my computer with the essay in front of me and othertask the crossword."