A group originally set up in the early 1960s to fight crime in Los Angeles, CA, USA (West Coast OR Left-Side) but was then turned into a gang full of crime.
Crip stands for:
'Community Restoration/Revolution in Defence'
Blue is their colour.
You know when somebody is a Crip in Los Angeles when all they wear is blue with a blue flag usually tied on their mouth, left wrist, left of their backside or on their left knee.
"...I keep a blue flag hangin' out my backside but only on the left-side, yea that's the Crip side!"
~Snoop Dogg in 'Drop it like its Hott'