1) Seeing violinists rock out.
2) Hearing All Along the Watch Tower played live
3)Seeing/hearing James Callis sing a called Spooky which is about, "you know, those times when two people have this sexual chemistry and you can tell the exact reason why"
4)Seeing James Callis rock out to music from a balcony and then clap and giggle like a little girl.
5)Hearing 400 BSG fans chant, "So say we all!"
and the best part of the evening...
Seeing Edward James Olmos's impression of a bear! this was prerecorded so one can only hope it will be seen on the season 4 DVD extras.
For those who were there feel free to add more...