For kicks... maybe it's been done before.
#1 - Metallica at Ozzfest 2008. 10 minutes from my house. Ozzy played before Metallica and could've headlined... AND had Zach Wylde on guitar (sp?). Metallica was as good as I've ever seen them (I'm a big fan) and the crowd was awesome.
#2 - Harry Connick Jr - he's a bad mother on that piano...crooner stuff aside