fave web games

I though about posting this in the games section,
but it's not an actual game, it's discussion

What are your fave web games?
flash, PHP, JS based. Anything.

And to make it more webforumzy, comment on the development/design of it (if you can be bothered)

Since all you want to know is what online games do people like, why did you think this was necessary? I don't play online games, but I am sure there are many here who do.

There are a couple of Flash games that I really like from onemorelevel.com. They're mostly puzzle games, here's some links:
http://www.onemorelevel.com/games.php?game=328
http://www.onemorelevel.com/games.php?game=169
http://www.onemorelevel.com/games.php?game=357
http://www.onemorelevel.com/games.php?game=173

I also like this one:
http://tank-assault.freeonlinegames.com/

And this is a kool flash version of Tower Defense. I know there are lots out there, but this one's my favorite:
http://www.candystand.com/play.do?id=17995

I haven't the foggiest clue about the development / technology / design used....

I like those tower of defense ones.
i spend ages on them for some reason

me too. I usually play them when I'm at school and bored stiff.

(Some of our teachers are so old they should have retired before I wuz born!)