From The Simpons Episode 7G02, Bart the Genius. The family is playing ScrabbleTM. Bart places down this word, scoring it as "twenty-two points, plus triple-word score, plus fifty points for using all my letters." Homer grabs Bart, calling him a cheater and asking him to define the word, to which Bart replies, "a big, dumb, balding North American ape. With no chin." Marge adds, "and a short temper." Enraged, Homer lunges at Bart, and Bart escapes, saying, "Kwyjibo on the loose!"

It is also the name of one of my favorite yo-yo tricks. It's a sidestyle trick that looks impressive as it involves a pop-up and quick hand transitions.

Start with a trapeze. The next series of steps should be done quickly and smoothly. Toss the yo up, and intercept the Freehand-Yo segment with your Throwhand. Your hands should be switching positions now (Throwhand crossing over Freehand), and you should catch the Yo on the Freehand-Throwhand segment. You will end up in a really funky hold with no name, which you will flip 360 degrees (so that your hands uncross and cross the other way). You will now be in a one-and-a-half mount (it doesn't look like it, but it is).

The last few steps should be done as one fluid motion. You will pop the Yo up, sending it outside towards your Throwhand. This is the tricky part. You have to intercept the Throwhand-Yo segment with your Freehand as the Yo is popping up (and to the side). If you do this, the Yo will start to drop down. Continue moving your Freehand over the Throwhand (to uncross) so they are on the same horizontal plane. The Yo should be landing on one of the bottom Freehand-Throwhand segments, the segment of string closest to the Freehand-Yo segment. You will end up in a Double-or-Nothing. Transition into another trick, or dismount.

To summarize: Trapeze, Toss up, catch in unnamed hold, 360 flip to one-and-a-half mount, pop up, catch in a Double-or-Nothing.