I think gambling websites or games are not meant to have this jackpot thing sometimes they have it with the whole users in the websites but already with a price of just a few hundred dollars.
Some are suggesting the freebitco.in but their are some allegations that about the jackpot in the websites since their is no one winning the jackpot ever.

I think it would be safe just to stick with the regular gambler play or games instead of this jackpots.