What I have done for other companies:
Vampires vs Werewolves at Chipin:
I created a top 10 game Vampires vs Werewolves Facebook app using PHP in my free time in Hawaii, then converted it to ChipIn, my employer, and other variations of VS were released, then sold after I left to Buddymedia.
Trafficcast:
I installed the Valhalla routing engine on my own without being asked as a competing product to their 3rd party stuff and created an Android app to use the Valhalla data as well as open street map which I setup on Linux for navigation and turn by turn directions for free vs paying a 3rd party. Told my manager about OpenStreetMap, and he had a backend developer start using it on Linux because I did mobile.
Trafficcast, I used voice control from open source cmusphinx and added audio output of directions to navigation and audio input for certain keywords while navigating, without being asked. They were a cool company.
Naval Surface Warfare Center:
I created pc macro to automate the conversion of digital files. we were doing it by hand before. sad to me how it was.
Profitlogic:
Without being asked introduced ajax/XMLHttpRequest when there was no such thing in the app currently. it was used for searching/filtering a grid of data faster than a reload. did a functional and design review, and it passed and added the code.
LTX:
Found many bugs as a QA Engineer intern. Made presentation on exploratory testing. Without being asked, made setting up automated tests easier by editing the header of an image in a script instead of manually taking a screenshot with the runner testing suite.