Custom screen locking application for Windows (similar to sLock on Linux/Unix). Designed to protect work / confidential data on public-use workstations (at university labs, libraries, etc) which generally also contain DeepFreeze or other snapshotting software.
This application is completely portable (no installation required): simply run the .exe, set your password, and click ok. This will lock your session so you can go make coffee or whatever it is you do.