You are who you surround yourself with. You tend to be more productive when you hang out with like-minded people.
I usually work solo on my personal projects, and it's damn tiring (on the plus side, I can do whatever I want, haha). I do have a partner in one of my startups, but since my internet is crappy and my co-founder lives in a different continent, communication is hard.
So it was a very refreshing experience when last month I attended Google Hackathon App Engine. It was a very productive weekend indeed.
From Wikipedia: A hackathon is an event when programmers meet to do collaborative computer programming. These events are typically between several days and a week in length. A hackathon refers not simply to one time hacks, but to a specific time when many people come together to hack on what they want to, how they want to - with little to no restrictions on direction or goal of the programming. Translation: party for geeks.
I didn't manage to launch anything there, but I made significant progress; made some friends too. Looking forward for another similar events. So guys, if you have the chance to attend such event, don't miss it :)