ESPN soccer analyst and former US soccer player Janusz Michallik was asked a question about Manchester United picking up Robin van Persie from Arsenal while on ESPN2. Well, Michallik stumbled on his response and thought he was off-air.
Except he wasn't.
(Since ESPN won't let me embed the video onto the page, here is the link)
Gotta give credit to Michallik though. He composed himself pretty well and finished cleanly.