Math
GeoGebra
GeoGebra: open-source app for learning geometry, algebra, and calculus.
Derive
Derive: powerful tool for solving math problems and making graphics.
GeoEnZo
GeoEnZo converts screen to chalkboard, draw shapes, scientific calculator.
Atanua
Atanua: create logic circuits easily with drag-and-drop interface. Great for students.
Free Jetico Scientific Calculator
Jetico Scientific Calculator is a comprehensive, versatile tool for calculations.
CaRMetal
CARMetal is a user-friendly geometry program with advanced features.