Laboratory: Virtual Experiment/Viscosity Explorer: http://www.planetseed.com/laboratory/viscosity-explorer
PhET Simulations: http://phet.colorado.edu/en/simulations/category/new
Fly a Hot Air Balloon: http://www.sun-sentinel.com/broadband/theedge/sfl-edge-balloongame,0,843241.flash
Circuit Construction: http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc