I dunnit now.
I wanted to do a little trigger work on my new FN TSR XP 300 WSM, so I set out to pull the stock off. The bolts were really tight from the factory, this was the first chance I've had to tear it down all the way. So I held some good steady pressure on the front bolt, and learned not to use the nifty Allen wrenches with the any-angle-ball on the bottom. SNAP! It broke and left the tip of the wrench wedged in the bolt head, flush to the top.
Any safe and nifty ways to extract? For reference, it's a 5/32 wrench.