It denotes a good, exciting or crazy time not disimilar to exclaiming wow or awsome.
The phrase os often used in combination with a rhyme i.e see the crane in the rain from a train it's insane. Don't be lame see the crane while you drink champaign it won't cause you pain etc.
alternative spellings are common
see the krane
s33 the kran3
see t3h kran3 etc.