Night Clubbing?
Peace be unto you,
It is a sin for someone, Christian or not, to do something that is sin. The act of going to the night club is not a sin; one's intentions and what one does there could be sin. If, for some reason, God has sent you to this night club to glorify Him in some way, then it would, obviously, not be a sin. But, if you're going to be putting yourself, willingly, into a situation where you know that you might sin before you leave, I think it is a sin to do so.
I voted "Maybe" because the act itself is not a sin, and there are conditionals.
Matthew 9:10 And it came to pass, as Jesus sat at meat in the house, behold many publicans and sinners came and sat down with him and his disciples.
Matthew 9:11 And when the Pharisees saw it, they said unto his disciples, Why eateth your Master with publicans and sinners?
Matthew 9:12 But when Jesus heard that, he said unto them, They that be whole need not a physician, but they that are sick.
Matthew 9:13 But go ye and learn what that meaneth, I WILL HAVE MERCY, AND NOT SACRIFICE: for I am not come to call the righteous but sinners to repentance.
Galatians 6:1 Brethren, if a man be overtaken in a fault, ye which are spiritual, restore such an one in the spirit of meekness; considering thyself, lest thou also be tempted.