Real people playing real instruments and catchy songs. It was almost Beatles-like with all these screaming girls... screaming and screaming.
A lead singer that plays bass at the same time has always intrigued me. Add to that, 2 screaming guitars and pounding drums and you're sure to have the ingredients for rowdy rock. The sound was made smoother by having a 5th musician. Though not a regular member of the band, a fine musician (that I do not know the name of) also played. He was kind-of hidden behind some monitors, but was a versatile musician playing keyboards, guitar, percussion and vocals. This made for sweeeeeeeeeeet sound.
I believe the songs they played included:
Night Drive, Dirty Little Secret, Happy Endings, Move Along, Swing Swing, My Paper Heart, Top of The World, Stab My Back, It Ends Tonight, The Last Song
If you haven't checked 'em out, you might wanna give it listen.