Shapespark is a company that we have started with my friends Wojtek and Jagoda. We are building a service for professional architects and interior designers to create WebGL-based real-time interactive visualizations. Our site and our first visualization is at www.shapespark.com.
A one day hack based on Speech Trainer. The application replays everything you say with a short delay, which momentarily confuses the brain and disturbs speech. 'Great...when it is working' to cite one of happy users.
An Intrusion Detection System for Firefox. I had a privilege of being mentored by Len Sassaman while working on Firekeeper during the Google Summer of Code. The project is no longer maintained.
HTTP referer and phishing
HTTP referer passes sensitive information to untrusted parties, the information can be used to make malicious content seem trustworthy.
Out of Kernel FileSystem
An experimental virtual filesystem for Linux that works entirely at the user level and does not require any kernel patch or module. Source code and documentation is on sourceforge. If you know Polish, you may be interested in a Master's Thesis about OKFS. It starts with high level explanation of how Linux file system works.
A mingetty productivity enhancing patch for dinosaurs that still work in a plain text mode. It allows to automatically log in with a name of a user that is already logged on some other virtual console. The feature is currently used by about 0 users, but the number grows exponentially. See patched version, original is on sourceforge.