Formal:
* Magsaya tayo nang husto. (Let's have a lot of fun.)
* Magsaya tayo hanggang sa umaga. (Let's party all night.)
* Magpakasaya tayo nang todo. (Let's have a really good time.)
Informal:
* Mag-inuman tayo nang todo. (Let's drink heavily.)
* Magsaya tayo nang bongga! (Let's have a blast!)
* Mag-wild tayo! (Let's go wild!)
More Literal:
* Kulayan natin ang bayan ng pula. (This is a literal translation, but it doesn't convey the meaning of partying hard.)
Choosing the best translation depends on the context and the desired tone.
For example, if you are trying to say that you want to go out and have a wild night, "mag-wild tayo!" or "mag-inuman tayo nang todo" would be appropriate. However, if you are simply trying to say that you want to have fun, "magsaya tayo nang husto" or "magpakasaya tayo nang todo" would be better choices.