Some of my IRC friends from the 90s are some of my closest friends now, too. It's cool 'cause they're geographically distributed so I have people I'm tight with in almost every major country.
Interestingly enough, one of my closest friends in my city I first "met" on the GNU Screen mailing list. I met him randomly at a conference here after moving and recognized his name.
Also, local user groups are good places, too.
PS: Freenode irc is full of dorks, but it's a good starting point. Try EFNet or one of the smaller hacker darknets (e.g. Buttes or hardchats or antisec/anonops) for the real motherfuckers.
If you're in college right now, and especially a top-tier university, try to meet as many people as possible. Don't miss this opportunity; your network will be invaluable once you're done with school. College is a great place to step out of your bubble and college admissions committees usually do a good job of putting a diverse group of interesting people in one place. Meet people from different backgrounds, countries, and majors. Even though you may not realize it now, you will one day need most of the people that you meet in school.
The Geekup template would be easy to replicate elsewhere (it's essentially a site and a mailing list, though I don't mean to denigrate all Andrew's hard work!). Personally, it's been a great source of contacts and friends, and I'd love to see the model expand elsewhere.
I also find a lot of interesting and smart people at Barcamps; there are enough regulars that attend a LOT of Barcamps (again, I'm in the UK, and elsewhere may vary), and they're usually great fun.
Also: a lot of (most?) people are very interesting if you look well enough. Not everybody seems to be interesting, but once you get to know people well, they might surprise you.
Networking through it also often leads to people from neighbouring groups, including artists, academics, entrepreneurs, politicians, activists and so on (many of whom might not self-identify as hackers/makers).
I'm in a large metro area so there are professional, hobby, social and sporting/outdoor groups of all types. I've met folks from hikers, body builders, travelers, sci-fi readers, robotics enthusiasts, radio operators to MSSQL DBAs.
Since I'm on my computer all day and at home a lot, I have to go to events to meet people which I'm getting better at.
Its the only place I bother going for a good time here in Vienna ... ;)
Want to know something more random? I happen to be in Wien right now on vacation :) Definitely going to check this out...
edit: typo
http://beta.hackersandfounders.com/faq/meetups/is-there-a-ha...