I'm going to count all the bands I saw at Warped Tour yesterday.
Queen with Paul Rodgers (2006)
Get The Led Out (2007)
My Chemical Romance (2011)
Third Eye Blind (2011)
All Time Low (2012)
Sleeping With Sirens (2012)
We The Kings (2012)
Memphis May Fire (2012)
Senses Fail (2012)
I Call Fives (2012)
Chunk! No, Captain Chunk! (2012)*
Every Time I Die (2012)
Vanna (2012)
Man Overboard (2012)
iwrestledabearonce (2012)
Phone Calls From Home (2012)
Mighty Mondo (2012)
Mayday Parade (2012)
Chelsea Grin (2012)
Streetlight Manifesto (2012)
Yellowcard (2012)
* = I met them as well.
I also met New Found Glory, but couldn't catch their set cuz we had to leave to beat traffic.
U2
White Lies
Passion Pit
Silversun Pickups
Muse
Thrice
Circa Survive
A Perfect Circle
Green Day
Placebo
Umphrey's McGee
Mindless Self Indulgence
Bad Religion
Tiger Army
Flogging Molly
Horrorpops
Gogol Bordello
Ozzy Osbourne
Static-X
Lamb of God
Slayer
Killswitch Engage
Best list.