First and foremost, it's about making like-minded friends and reliable roommates.
Ideally, the goal is the create a valuable development team in the process - and then take on fun and creative projects through opportunities like ycombinator and kickstarter.
That being said, I am a Ruby developer. I do think that anyone I pair-program with should be familiar with Ruby.
However, I am not tied to the constraint that I have a roommate that is a Ruby developer.
It's a little tight.
I've updated the website to say Textmate is preferred rather than required.
The "heroku ftw!" remark is just a deployment option that I added in there to express my feelings towards the company. Technically it doesn't matter what platform we work on. I just happen to find them to be a rather unique and creative service that suits my needs.
As far as RSpec - it's a matter of personal preference, but again... technically it doesn't matter.
Anyone who doesn't meet the requirements EXACTLY should not feel unwelcome in sending me an email :)