[JonWood]

I'm in a similar company at the moment - it's not quite GitHub, but the atmosphere of smart people working on things they love is there. Since I started they've also started adapting to the "Work when you want, where you want" approach as well ;)

When looking for work a big requirement was that I could work from home, and have Wednesdays off - filtering down the opportunities was just a case of mentioning that in the initial contact with a company I was interested in. No one you want to work for is going to be offended at you pointing out something that could be a problem early on in the process so long as you go about it politely.