Launchy is a free and open-source muti-platform application launcher.

Find and Run Robot (FARR) is a program for keyboard maniacs -- it uses an adaptive "live search" function to rapidly find programs and documents.

UMLet is an open-source Java-based UML tool designed for teaching the Unified Modeling Language and for quickly creating UML diagrams.

Enso Launcher is designed to give you instant access to your applications and windows.

Jitsi (formerly SIP Communicator) is a free and open source multiplatform voice (VoIP), videoconferencing and instant messaging application.

Keypirinha is a fast launcher for keyboard ninjas on Windows.

UnMHT adds MHT file reading/writing support to Firefox and SeaMonkey.