famous extras/cameos in movies

[HugoM]

i was watching The Dead Pool on tv the other day and noticed Guns n Roses (well at least Slash, Duff McKagen and Axle) in the background during a scene at a funeral. it reminded me that The Clash appeared in the background of a street scene in Scorsese's King of Comedy. can any of you think of any other famous cameos or extras in movies? by this i mean blink-and-you'll-miss-it type appearances, not ones where the stars actually had lines or anything. it doesn't have to be musicians, it's coincidental that my examples are rock groups.