The latest survey shows that the average LessWronger who entered his SAT or ACT is roughly in the top 0.11%. This is insanely high. For comparison, top 2% can be Mensa members. I do not know the correlation between SAT/ACT and IQ, but I know it's fairly high. Anyway, I'm very curious to see the average score on a real, culture-fair IQ test. Those are the only two tests that are free, online, correct and culture fair, from what I know.
http://www.cerebrals.org/wp/tests/jcti/
http://www.etienne.se/cfnse/
Many people would prefer not to have people knowing their scores. That's great, but please please please do post it anonymously. Especially if it's a low one, but not if it's low because you rushed the test.
JCTI might take a while, so I recommend keeping your answers on Notepad in case you want to leave it and continue later.
Edit: I have included polls, thanks to the commenters.
Post your score here: http://lesswrong.com/r/discussion/lw/fqq/average_iq_on_lw/7yad/
It strongly depends on the person, some are faster than others.
JCTI takes at least an hour for nearly all people with high scores. 2-3 hours isn't too much.
CFNSE takes 2 to 5 hours, according to the estimation on the website - it's an accurate estimation IMO. A possible strategy is to do it "quickly" (for 2-5 hours or so) and leave everything you couldn't answer definitely for the last. Then spend 30-60 minutes on each of those. I think this isn't going to artificially inflate your score, and I'm quite certain that someone with 100-110 IQ can't figure out the patterns for any of the hardest questions, even if he spends hours/days on each.