game downloads:
Arcadetown.com
Many other sites have the option to download the "full version."
demo downloads:
FilePlanet:
http://www.fileplanet.com
GameSpot:
http://www.gamespot.com
FileShack:
http://www.fileshack.com
Worthplaying:
http://www.worthdownloading.com
3DGamers:
http://www.3dgamers.com
GGMania:
http://www.ggmania.com
I havn't tried downloads from all these sites, make sure the site's
reliable.