Gamcore is a website that features sex-themed Flash games and they have a gay category that's worth taking a look at if you're interested in some gay porn games. I counted a total of 37 games in the gay category, although there are a few here that certainly don't come across as gay at all to me. Anyway, for those that do, you've got greats such as 'Fingered', where two dudes finger each other over a trash can, 'Gaytrix reloaded', a parody on The Matrix and my personal favorite, 'Ultimate Orgy', where you'll be able to watch Chuck Norris fuck Godzilla and Jackie Chan get it on with Batman.
The range of content here is very interesting and the quality of the Flash games is a little better than most sites. Sadly, the fact that it isn't entirely devoted to gay productions and non-gay games have slipped into the category doesn't make this an ideal location for gay porn games. Still, check it out if you haven't before - there's still some fun to be had.