If your looking for any game i would recommend a really popular one that you most likely have heard about by now called league of legends, its a MOBA type of game with a decent learning curve that most people enjoy
Look up MMO Bomb or MMO Hut, surprisingly its not filled with a bunch of RPGS and have some pretty solid FPS's such as PlanetSide 2 if that doesn't help try steam and click on "Free Games".
If you would like a list of games I would be happy to make you one if you provide info on the games your into!
If anyone is looking for the good old point and click adventures for free. I downloaded pretty bunch at GOG.com for free. Check it out I as a 37 year old gamer loved the time of point and click adventures
A good free mmo that I would like to recommend is blade & soul it's like guild wars 2 meets world of Warcraft meets Tera very good in depth mmo every one should try it has lots of classes and is very easy to learn and play also has controller support its free to play