Yes sometimes your friends will give you a game they no longer want
Actually, there is a game called poptropica. Only membership has email addresses on the game.
At Goldies Games : http://www.goldiesgames.com
woozworld
www.direct2drive.com has downloads for many different games. Other methods of downloading games without paying are illegal.
no where
a really good site for games without any downloads are pog.com and umgames.co.cc
There are ghost games for small children to play both online and with friends. These online games can be played in-browser without additional downloads.
The DSi downloads games from its own DSiShop, and the 3DS downloads games from its own eShop.
as far as I can tell, no. Free realms is the closest to membership without having to splash out. There are no good online games that dont need downloads
One game I know that you dont need an email is poptropica.
There is habbo, club penguin, runescape, millsbury, neopets isn't really one but it is good fun
I don't think there are any.