If you mouse-over the Games link at the very top of the page, it shows you some stats at the bottom of the list that pops up. One of them being "# People Online". However, this count of people seems to be a lot higher than the amount of people actually logged in to games. It may be counting anyone connected to the pager, or counting suppressed rip players... If that isn't the case, would it be possible to add another stat for "# Playing Games", or something along those lines?
At the time of this posting, it was reporting about 3,500 online, but the listed games (including anime) were totaling closer to 1,000. That's a rather large mass of hidden users...