1. 28 years, 5 months, 25 days (Dance Hall Crashers)
2. 23 years, 10 months, 22 days (Hot Rod Circuit)
3. 22 years, 10 months, 11 days (Matthew Sweet)
I can't fathom DHC will be beat any time soon.
But also:
David Bowie (saw Sufjan Stevens and the Delgados the same night for $21 instead of the $70+ for Bowie)
Include reasons if you like:
Rolling Stones (play rehearsal)
Johnny Cash (I dallied)
R.E.M. (play performance)
Nirvana (canceled, college declined to pay requested $500 appearance fee)
But also:
David Bowie (saw Sufjan Stevens and the Delgados the same night for $21 instead of the $70+ for Bowie)