Anyone over the age of thirty that faithfully watches and gets overly excited about the show "Glee".
Dave: "Dude! I can't wait for tonight's show! Brittany is doing Britney! I'm Gleeking out! Can I hang out and watch the show in your room with the other Gleeks? I'll make the popcorn!"
Ariel: "DAD! GROSS! You are such a Gleezer! Why don't you get a grip and go watch Dancing with the Stars in the living room with Mom?"
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.