A word that literally means nothing takes on a whole new meaning in this game led by house musician Jonathan Coulton. Contestants must identify words that, when the letter "O" is added to their end, become different words. For example, adding nada to what the "D" stands for in CD-ROM — "disc" — produces a music genre — "disco."
UPDATE: Since this episode originally aired, we learned that Lamb Chop, Shari Lewis' sock puppet sheep, also testified before Congress, in 1993, in support of quality children's television. So while Elmo was not actually the only non-human to testify before Congress, he is in very fine company.