I know this pic is everywhere but I just found the source and wanted the story.
source (jan 31,2011)
Day 203: So... A Girl Walks On To The Set Of GLEE...
A work-related site visit to Paramount Studios turned into a pretty Glee-rrific day. My boss and I were supposed to meet an event planner there and I noticed that there were lights, equipment, and a few director's chairs scattered about. I thought, "Hey... the font on those chairs looks like the 'Glee' font." Then I overheard a woman say, "Ok, so then after that they're going to start singing [song title deleted so that I won't spoil anyone] ..." And that's when I knew that we just walked on to the set of Glee.
Before I knew it, I saw Chris Colfer and Darren Criss just hanging around and chatting. Unfortunately, I took this picture right after they left to film (obviously). But hey, I guess you'll just see them on TV :)
(a comment on the page)
I wish I actually met him. I was much too chicken to actually approach and start small talk -- especially since he was also talking to Chris Colfer! I'd just die!