Golden Boy got his name after the crew got him drunk, dumped him in a piaza and emptied their bladders on him. He later became better known as 'TCC'. Thankfully left.
One bloke (now left, but possibly back as a reserve/aux) didn't like the sncos using the normal abbreviation of his first name as it sounded 'too italian'. Spent the rest of his time called 'Luigi'.
Then their are the one's reserved (not necessarily fairly) for female aircrew:
Milkshake - nice, but thick.
Emu - a big, ugly bird that can't fly.