Whats a good time to get in line for a sold out event?

Concord usually has virtually no line. To play it safe, you could show up a half hour or hour early and be fine.

I went to a Subtronics/Blunts n' Blondes show last week and I spent a while looking for my friends, but even after that I spent at least 30 minutes standing in line. In below freezing temperatures.

I agree with danielie, I have been to several shows there including sold out shows and they do great job getting people in-and-out, it's laid out well for ingres/egress. It's a comfortable theater, and the acoustics are good!