Well, unless you are going to brand the site and make is something of the level or better to what the professional poker players and major game sites offer, it will be a tough road, but not unprofitable if you do it right.
However, I have a number of clients that have sites like this and while all are very different in appearance, level and profitability due to their owner's efforts and investment in the respective projects, it is far more profitable to go with a free poker/game site, build a community of users and then promote ads/banners/offers within your system, as something they are used to seeing in those types of sites.
Banners and spot ad rotation works best from my experience.
Focus your cash flow funnels from a couple of major areas:
* Free play limitations/affordable membership access with a point system rather than real cash.
* Advertising clients paying to have their ads in your site rotation and solid affiliate offers that make sense to your clients.
* Player client purchases from your affiliate ads.
If you plan to make a real profit from the ' gambling ' aspect of it, toss that idea, as there is slim to no chance there unless you are going to seriously invest and compete.