I have not come across a place where I felt more immediately at home and enjoyed as much as geekhack. Its odd and eclectic and wonderful and even grammatically correct more often than not.
I felt the same way when I joined up about a year ago and I have to say that I was expecting to stick around, but for some of the reasons you brought up, the fit felt right. It's not too large and not too small. It's not too young and not just full of jaded oldies. There's a good mix of three things you don't often see together: IQ, fun, and sanity. Finally, it seems that a lot of people here really do care even as cantankerous as a lot of us can be (not all on the same days thankfully).
The more grammatically correct part than usual is more than an added bonus. There's nothing that gets older faster than a board full of people who write everything in shorthand like they're texting or in a chat room.
I've been parts of various online communities starting in the mid 80's. I've had a lot of online homes, but the Facebooks and MySpaces of the world took over, but those services just don't suit me well. Until I ran into GeekHack a year ago, I was without a place to hang my hat for the longest time since I got started.
iMav, thanks and to Ripster and everyone who spends a lot of time looking after this place in their own way, thanks!