So, one of the things about nerds is that they're sticklers for details. Let's take a simple quiz to gauge your ranking in the nerd herd:
1) Approximately how old is Yoda? (n00b nerd)
2) Gandalf was of what race? (well-qualified nerd)
3) What are the "Eyes of Ibad" (overly-qualified nerd)
If you're one of the qualified nerds, you're probably qualified to edit one of the nerd wikis hosted on Wikia. If you're not one of the qualified nerds, you'll be amazed at the sheer amount of time that some people have on their hands. I've grabbed just a few of the better nerd wikis to peruse, but be forewarned: they are rabbit holes, and you will come out the other side sporting Spock's immaculate beard.
- http://seinfeld.wikia.com/ Seinfeld (781 pages)
- http://starwars.wikia.com Star Wars (107,528 pages)
- http://en.memory-alpha.org canonical Star Trek (36,523 pages)
- http://memory-beta.wikia.com non-canonical Star Trek (43,000 pages)
- http://lotr.wikia.com J. R. R. Tolkien's Middle Earth/Lord of the Rings (4,811 pages)
- http://ansible.wikia.com Orson Scott Card's Ender's Game (479 pages)
- http://tardis.wikia.com Doctor Who (37,199 pages)
- http://dune.wikia.com Frank Herbert's Dune (2,543 pages)
- http://marvel.wikia.com/ Marvel Comics (116,708 pages)
- http://dc.wikia.com/ DC Comics (79,778 pages)
I'm actually quite surprised that Marvel edges out Star Wars and that the Star Trek wiki is so puny in comparison. Of course, the entire Star Trek universe was split into canonical and non-canonical sources and each entry tends to be extremely exhaustive (5000 words for Captain Elias A. Vaughn ?), because Trekkie.
There are also tons of video game wikis, a Disney wiki, and all sorts of other stuff deemed too "low-brow" for the almighty Wikipedia, so check it out.