I was trying to follow the link to GitHub in this question:
What are some interesting features of the EveryBlock.com source code?
but it contained a percent-escaped underscore, though the source didn't. Escaping the link broke it (which may be GitHub's fault, but nevertheless...).
Specifically, the link should have been (and was written in the source as):
http://github.com/brosner/everyblock_code/tree/master
but was rendered as:
http://github.com/brosner/everyblock%5Fcode/tree/master
I couldn't figure out any way to fix the link so it worked (aside from sending it through a URL shortening service or similar). There's no need to escape _ in URLs; perhaps it could just be passed through. Or is there some way to do this?