[RagnarD]

Try Meetup.com. It's unfortunately gone downhill in many ways, but there are still people using it. Search for in-person meetups in your area and if any look interesting, sign up and go to some events.

[erikig]

Yep, meetup.com, eventbrite.com and for the musically inclined residentadvisor.com and dice.fm.

The trick for me was to offer to help with the organization of the event, it is more rewarding and makes for more lasting connections.