Originally used as a slang term for "What's Up?". popular use extended it's meaning to such definitions as: "hello" "good day to you sir" "your foot is in my pie" "I think I have fractured my pelvis" etc.
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.