Reading this article by David Segal about his remembrances of great unscripted rock concert moments from his days as a music critic at the Post brought back so many old memories of when I used to go see bands three or four nights a week that I was inspired to ask our loyal IRONMOUTH readers to write in with their own favorite Rock Concert moments.  I'll start us out:

My favorite rock and roll moment happened at the 9:30 Club in Washington DC in October of 1999.  The concert (dream) bill was Cheap Trick with Guided by Voices and some unknown Boston band opening.  During the Cheap Trick set, in the middle of  "Southern Girls" suddenly Bob Pollard from GBV drunkenly stumbles onto stage holding a half-drunk bottle of Jack Daniels, throws his arm around bassist Tom Peterssen's shoulder and starts belting out the chorus with the rest of the band.  The crowd went fucking crazy and I still reminisce about it with friends to this day.

Have fun!