This section is somewhat controversial. I like to use one, but others claim that it just gets in the way. IMHO, it's a great chance to show off other abilities that just might be relevant, such as foreign languages, pilot licenses, security clearances, etc. Beyond that, some say it shows misplaced priorities, but I say it helps show "well roundedness", by putting in a hobby or two that are completely unrelated to work. After all, a computer-obsessed geek may Know His Stuff, but is likely to have rather stunted social skills, which may be a handicap in some jobs.
Be careful -- avoid anything controversial, or on any topic often subject to discrimination. Don't mention a hobby such as collecting machine guns, or a community activity based on your religion. Many companies will immediately roundfile any resume mentioning such things in any way, out of fear of lawsuits. If they interview a candidate with something controversial on his resume, and don't hire him, he can (and often will) claim that he was discriminated against because of specifically what he wrote. For instance, someone mentioning that he's a deacon in the local parish could claim that he was not hired due to anti-Catholic bias... but a firm policy of roundfiling any candidate that mentions religion on the resume at all, can be a pretty good defense.
Things that used to common are now not only frowned upon, but outright prohibited. Do not list things such as marital status (if you want them to know you can or can't travel, just say that), number and age of children, career of spouse (if any), etc.
If it's relevant, you can list what country you are a citizen of. (Here in the Washington DC area, there are lots of job openings that are for US citizens only.) Otherwise, better not, especially if you would need to get visa sponsorship. Let them read your resume, fall in love, and then find out they'll have to go through bureaucratic red tape to get you. Otherwise, your resume would probably be roundfiled immediately.
There are some further controversial things that can go here or not; your call. For instance, mentioning that you are a member of Mensa may impress some people, but may scare off some others or come across as snobby -- but ask yourself if you'd want to work for/with someone scared of smart people. (There is an old saying: first rate minds hire first rate minds; second rate minds hire third rate minds.)
Above all, don't go overboard. At a guess, three lines maximum.