Ozzy in '83... he was fat, drunk, and not very good.
Uriah Heap w/ Def Leppard... Lep was great, UH never played. (1983)
Queensryche with AC/DC... AC/DC was fantastic, but the speaker stacks blew over early while they were setting up and injured a band member so, Queensryche never played. (1986)
Eddie Rabbit at the World's Of Fun in Kansas City, (late 1991 I think) just because it was there.
Day On The Green in San Jose in '99 or 2000... filthy, stinking, moshing drunk animals and music from the various bands all sucked. Dave Mustaine was fucking drunk. Sammy Hagar was good, but last.