As to how, the crack propagated from the weld (hard to see in the picture, it started right along the weld on the downtube side). I had noticed a minor clicking when I braked over a few rides which I figured was a headset issue, tightened it up, rode it another two times and then found that crack after a ride when I was cleaning it (I wipe down the bike after every ride, so the majority of the crack happened that last ride).
Fortunately I had already begun piecing together a new bike (see my Felt AR thread) so wasn't without a bike for too long.
shlammed, it's a custom size (see geometry here). I haven't actually bothered to deal with it yet. I'm not the type of person to have multiple bikes kicking around so am probably going to sell it, I just haven't looked into if selling it broken and having the buyer repair it or repairing it and then selling it makes more sense.
Here it was in all it's glory. RIP
