http://chriswarbo.net/git/warbo-utilities/branches/master/sy... just runs a given command in a given directory, e.g. `inDir ~/Pictures convert MyPhoto.jpg MyPhoto.png`
Really simple, yet I use it a lot, e.g. for remote mounts where Emacs can slow down if I "cd" into it, or in loops `for DIR in submodules/*; do inDir "$DIR" git pull --all; done`
When I used to do Web development, I found http://chriswarbo.net/projects/repos/chrome-duplicate-tab-de... to be super useful. When opening a URL in Chrome, it switches to an existing tab with that URL if there is one.
I also made a simple Chrome extension which let me navigate Drupal test output using the left/right arrow keys. Can't find it now though :(