If so, check out the DOS Games Archive. Personally, I am not a gamer, but back in the days of DOS I played quite a few games. In my opinion, they were better then than they are now, simply because the focus was the storyline and gameplay rather than the graphics and cut-scenes which seem (to me at least) to be more prevalent today.

Unfortunately only some of the games have the full version available:

We have 232 DOS games in our archive that can be downloaded for free. The games are shareware, freeware, playable demos and full versions that are released as freeware or into the public domain.

Additionally, take a look at a site I have written about in the past: Abandonia which features lots more freely available games.

These two sites have enough on them to keep you entertained for quite a while. Enjoy.