Juvenile neighborhood nuisance; usually characterized by rudeness and general disregard for other people and property.
Other characteristics could include stealing, smoking, drinking, destruction, loudness and swearing.
That punk monkey broke my fence again. Those punk monkies are throwing rocks at cars, call the cops!
1:A set of Inline Skates that are bottom of the line; generally low quality or cheap Skates worn by beginners who want to learn to skate but aren't ready to spend a large amount of money just to find out they really don't like inline skating.
2:A pseudo-abrasive term, that is an informal way to tell someone their ride (not always inline skates) is cheap, basic, or bottom of the line.
You: "Those neighborhood Rail Rats
just strapped on some Punk Monkeys and knocked over my trash cans!"
You to a newbie skater
(friend): "You're riding Punk Monkeys!"