Interesting bio for Mark Salling who plays Puck:
Mark Salling is from Dallas. A guitar player and seasoned songwriter, Salling has performed and recorded with several different artists. He also recently released his debut album, "Jericho," on which he provided all of the instrumental and vocal tracks. He continues to write and record new material for upcoming records.
I like, how as an actor, he can literally turn on dime and go from a realtively "normal" look to a very dark and foreboding one with just a quick change in his expression. His character is clearly very deeply conflicted and he is able to show that in his performance. Puck's evolution (or the opposite) may be one of the more interesting things to watch as the show goes on.