This is really handy (on Linux and Cygwin) when you're working on a project that may not be in source control and you want to see what you changed recently.
I made this blog post, when it seems a trivial use of find, because I don't think the man page covers it well.
This command finds all files modified in the last 60 minutes:
find . -type f -cmin -60
emacsninja: Trapping Attackers With Nyan Cat
2 hours ago