Here's an excellent glossary of Carny Lingo, straight from the midway. A sampling:
BABY NEEDS MILK – When carnies see another carny flirting with the townies, they will often go by and say this just to mess up their buddies 'score'.
FLOSS or FLOSS WAGON – Cotton candy and a 'grab joint' that sells cotton candy.
GOING OUT HORIZONTAL – Working until you literally die on the lot or in winter quarters. Something not common among carnies.
KICK – Refers to the pocket where carnies keep the money they 'swing' with, i.e., "I saw Gizmo put that 'fin' in his 'kick'."
RUBE – Any kind of physical and sometimes, verbal fight. Originally meant a big fight between the carnies and the townies. When a carny saw someone hit a co-worker, they yelled "Hey, Rube!" and everyone who could bail a counter piled on. Also, a not very affectionate term for the towner himself.