Windows clipboard capture to file tool. Any new image placed on the clipboard is written to a sequentially-numbered file so that I can just hit various Print-Screen key combinations or I can right click an image in a browser and click Copy to capture it.
Python / PIL scripts to arrange directories of images into seamlessly connected wallpaper images.
Lots of email automation scripts, both sending and receiving. ( Pruning spam, marking all of my unread messages read, sending alerts for blog post updates. )
Scripts to convert filenames to all lowercase in a folder.
Startup scripts that forcibly turn off Windows options that I don't want because Windows update sometimes re-enables these.
Python/Bash + Cheese - Poor man's security system. I used an old netbook with the camera pointed at the inside door of a house I used to own take a picture of the door area and send it to me via email so that I could monitor to see if anyone had been inside while I was gone for an overnight trip.
Custom RSS aggregator scripts ... sends results to me in email so that I keep a record of the articles by day.
...etc., ...etc.