Just found this great blog with loads and loads of games. It's called Bunchball.com. It's said to be the leading provider of social gaming services. That means that you can add the games to your site through a Widgit.
You can actually play a match with someone online (you can even invite a friend to play with you). I tried out N-blox Evil Edition. They asked me whether I wanted to try out n-blox-tetris while I waited for someone to come along and play a match with me. I clicked "Yes".
It was great fun but I had to leave the site to take care of my baby. Might try it again tomorrow.
Don't blame me if you find yourself spending hours trying out the various games.