We had three team members working on this and only two good chairs, so we rotated. What you can't see is that we have two couches around the work area.
I'm thinking a $100 chair from Office Depot would be a good idea. (I'm an independent working from home, and I recently bought an Aeron, out of my own pocket) I get the whole long hours, bare bones startup incubator thing, but just like we often use MacBooks instead of $249 WalMart specials, seating isn't an area to skimp on! :-) (as for the couch, I think I couldn't do that for long as an alternative - my MBP Retina gets way too hot for that)
Hey this is Karl, the other Eventjoy founder. I actually spend a lot of time working on couches, so I was actually pretty happy :) Besides... we didn't have time to fetch another chair