Mine comes from three sources.
aj - my dad can't spell the name he gave me, Adrian. He always spells it "Adrain", so he started using aj. I liked it. Sure beats hearing "Yo Adrian!" every 5 minutes! (don't do it!)
the pool - Dad started a swimming pool business and dragged me into it kicking and screaming! I sold, installed, serviced and renovated many swimming pools and spas for 10 years.
man - I have a pe...whoa, this is a family forum! I am a boy.
When I set up my very first email account, I went with ajthepoolman as a handle. World wide fame and notariety have followed ever since!