to go out and celebrate; to go on a drinking bout; to get drunk.
zaszaleć, uczcić coś, zrobić rundkę po knajpach, pójść w tango, zabawić się na całego
They were out painting the town red last night.
Whenever they go to New York they want to paint the town red
It was the end of term and students decided to celebrate by painting the town red.