I know some of these have been posted in the Forums previously, but with the temporary change of GGOTD only offering the games on weekends, I thought it might be good to create a thread with all of them in one post. I use all of these that I will mention so if you have any questions, please let me know.
http://www.mostfun.com/ - All full version games you download to your PC, although it does install a Game Player. A short ad does pop up occasionally, but not enough to be annoying. Previously only available to play on XP, but they have just recently released some of their games as Vista compatible. I did notice that the Game Player does not load on Vista, just the games.
http://www.freeridegames.com/do/index - Same as above, installs a Game Player and short ads in games. Not as many choices as MostFun, but good anyway. Works on XP and Vista.
http://www.gamehouse.com/ - (Mentioned recently by Lonehiker) Extended play and Unlimited play games. Click on Download Games, then Extended play games. I'm not sure that their games are listed in the correct categories as I have Diamond Detective and it is actually unlimited, not extended. Works on XP and Vista
http://www.iwin.com/ - (Mentioned recently by Sukibabe) Click on "Free Games" and the entire list of Unlimited Trials comes up. Again a game manager and short ads. I liked this site as it had some games that the others did not that I had wanted. Works on XP and Vista
I have not had any problems with Adware or Spyware from these sites or games, either. I know there must be other sites like this out there and many links. I like these because they are newer games and not "flash" games (sorry, don't like these). If anyone knows of others, feel free to post them here.
PS - thanks again to everyone for the kind words and funny links in the other post earlier today. Much appreciated and nice to know that people I've never met are so kind and friendly. I love coming to this Forum to read, laugh, learn..... ;-)