I haven't tried yet, and I'm probably imagining it's going to be much harder than it is in reality.

For the first time ever, I broke off the nut and the end of the Presta valve core while airing my tire. Actually it was while taking off the pump head, so the tire was up to pressure and I was able to ride. But now how do I change the tube? I don't want to have to stick a pin through the tire!