Here is Jay Leno in a Doritos commercial from the late 1980s:
[youtube http://www.youtube.com/watch?v=NDpSp5EoX44?wmode=transparent]
Here is Bill Hicks absolutely murdering him with a standup bit. It's almost too cruel, but then you remember it's Leno and you just don't care. Important to note, this was done in the early 90s I think. Hicks died in 1994
[youtube http://www.youtube.com/watch?v=cfkvpcjNk7c?wmode=transparent]