1. The Teitho Challenge
http://teitho.waking-vision.com/modules.php?name=Intern&file=index
I love this monthly genfic challenge for stories mentioning Aragorn and/or Legolas. I admit I'm not a Legolas fan, but I love to read and and try to write each month stories about my beloved Aragorn. The stories are posted without names so voters are not influenced to vote for a friend or someone well known, so you know if your story wins it is solely on merit. I also feel at my most comfortable both reading and writing within the rules of the contest.
2. Stories of Arda
http://www.storiesofarda.com/index.asp
A canon friendly genfic archive which is very easy to post to and easy on the eye for reading and blessedly free of the Mary Sue's and non canon pairings found on some other sites. It is also easy to catch up with what my favourite authors are posting there, being a small archive.
3.Naice a Nilme
http://www.naiceanilme.net/index.php
A small friendly gen fic archive run on similiar lines to the Teitho contest. The owner is currently looking for someone else to take it over, so I hope it will thrive and continue.
There are many other places I love too such as the MPTT Archive and the Tree and Flower awards
http://www.lotrgfic.com/
and the annual BTME Challenge.
http://b2mem.livejournal.com/profile