There was one where I took the "Bob, Luis and the Train Tunnel Picture" sketch, where it starts sped up REALLY fast, and then when the train zooms into the camera you hear the Viacom "V of Doom" theme. The other was where I took the "Bunmaster" exercise show from "Rocko's Modern Life" ("And a one, and a two, and a one...") and had Sesame Street News interrupt it (using the "Cinderella Prepares for the Ball" sketch) because of how "Bunmaster" was always getting interrupted by special reports in the show.
Hmm, I'm starting to see a connection. Both use content owned by VIACOM in some way. Maybe SesameWorkshop doesn't want anything to do with the company?