1) Try to be more selective with the meetups you attend. Particularly, meetups focused around a programming language or a specific technology (Python/Hadoop/Node.js/etc) are likely to have more dedicated technical attendees. Bonus points if the meetup doesn't allow vendors/recruiters - that generally means that they like to keep the conversations focused on technology, rather than sales or job offers.
2) Hackathons. It's often encouraged to show up without an idea, form a team, and work on an idea for 24-48 hours. This is a great way to test-drive a partnership with someone who you might invite to work on a side-project. Chances are, by the end of the hackathon, there's mutual respect/trust among team members; the bonds you form by hacking together for a day or two are going to be far more conducive to working on new projects than the bond between you and your twitter followers.
3) Open-source projects. Pick an open-source project that you find particularly interesting. Sign up for the developer and user mailing lists, ask questions and answer them where you can. If you ask the developers where a good place to start helping out is, they'll often give you some easy ways to help out (improving logging / documentation / code style is often an easy first patch).
Hope this helps!