You cant do that in any online sites because we can use vpn if my ip is ban or we register again with another name or email account.
So its not a good suggestion its better to give him or her hobby or vacation than banning it to any gambling sites or in real because
If you still preventing him/her s/he still finding another way to play again on gambling especially for those who addicted..

Good idea. But not guarantee we can stay away from gambling.
My suggest to stay away from gambling lets go party with friends and dont remember about gamble or you can play the games offline.

because gambling is money, so I think you must to have a job with a high salary or enough for your life.
and start another interesting activity

If you were loosing what you cant afford to lose, then you should not gamble all of it in the first. DON'T EVER GAMBLE WHAT CAN'T YOU AFFORD TO LOSE

Try to not keep spare money than your immediate needs at you.Keep you Bitcoins in desktop wallet instead online wallet and keep your wallet one day behind the syncing.No immediate funds means no more gamble.

Seek help from a support group, they should be able to help you. Or get another hobby to keep you occupied so you won't have time to gamble. Or you could just play with "Fun Money" which some places offer where you can play without real money! Also, whenever you want to gamble, think about all the money you lost. Think about how it made your life bad.

Yes, take DarkStar's advice. The first step is realizing that you have a problem....but that's not enough.  You have to be proactive in your effort to change the behavior that is creating the strife in your life.  By seeking out the help from a support group, you will be able to learn from those who've been where you've been.  And, you'll be able to work together to find alternative activities to replace those activities which you know you should avoid.

he was just talking about fun. gambling is a hobby, a life style. there are ppl willing to ruin their lives just to stay cool.

and those people who were willing to wreck their lives just to have to stay cool were stupid. its just fine to gamble as a hobby but i am pretty sure those who consider gambling as a hobby only gamble what they afford to lose.

but if the rich people gamble just for fun, then the pleasure it would make him miserable and impoverished.