Skyrim Enhancing Mods
http://www.gamersnexus.net/news-pc/660-best-skyrim-graphics-mods
http://pc.gamespy.com/pc/elder-scrolls-v/1212918p1.html

Doom 3 Enhancing Mods
http://www.strategyinformer.com/pc/doom3/mod/41010.html

Other Mods
http://www.gamefront.com/5-hd-mods-you-must-try/

Note that are multiple mods for one link, except for the Doom 3 HD mod link.

Some require that you unzip files using an application such as WinRar or WinZip. If you don't mind torrents, you can get a free WinRar uncompressor in the following link.

WinRar Corporate
http://thepiratebay.org/torrent/4013597

uTorrent (to download torrents)
http://www.utorrent.com/

i already know how to do this. i have done it all the time on the sims and on San Andreas.

>>3 You may know, but that doesn't mean that because you know everyone knows.