Convenient “everything about physics” reference pages; GSU’s Hyperphysics http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html

Beautiful, cool link to a flash game exploring the SIZE OF THE UNIVERSE. http://www.newgrounds.com/portal/view/525347

The Falstad collection of physics simulations: http://www.falstad.com/mathphysics.html
Ripple Tank Simulation: http://www.falstad.com/ripple/

Refraction: Snell's Law simulation: http://www.lon-capa.org/~mmp/kap25/Snell/app.htm

Refraction: simulation using Huygens wavelets: http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=16

The PhET simulations are here http://phet.colorado.edu/index.php

A wide variety of Acoustics and Vibration animations http://www.kettering.edu/~drussell/Demos.html

Trun your computer into a sound generator: http://onlinetonegenerator.com/

Colors and the wavelengths that they correspond to http://eosweb.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html

Demo of Isaac Newton's explanation of satellite motion (cannon firing from mountain) http://galileoandeinstein.physics.virginia.edu/more_stuff/flashlets/NewtMtn/NewtMtn.html

Explanation of the machine that makes fabulous sparks: The Wimshurst Machine

An amazing FREE scientific calculator, algebra processor and graphing program: SPACETIME.

Another amazing FREE calculator, plus this one does algebra! Wolfram Alpha

--------------------- Project ideas ----------------------

Build Kelvin's Thunderstorm. To see a demo of this project look at this video. The part to look at starts at the end of the lecture. Jump ahead to about 44 minutes. Kelvin's Thunderstorm, MIT video. Try looking at the Wikipedia article.

Measure the electric field of the Earth. To do that, you could a special sensor called a field mill, or you could send a ballon up with a wire and measure the voltage. The wire on a balloon approach is maybe easier, but I haven't seen any discussion on the web. In either approach, I can help you build the electronics.

Make a digital clock with one of three methods for a timebase
1) Use a quartz crystal
2) Use the AC power line
3) Use a pendulum powered by an electromagnet

Build a seismometer, detect earthquakes. I can help you make a magnetic coil sensor and hook it up to a computer.

Build an electric guitar pickup. http://www.instructables.com/id/Make-A-Guitar-Pickup/

Make an electric motor.

Build an iPod amplifier and loudspeaker. See the "computer audio booster" circuit here: http://www.techlib.com/electronics/audioamps.html#computer

Her is a web pages with tons of project ideas: http://www.instructables.com/

------------------- Project Supplies ---------------------

All sorts of motors, gears, electronics, kits are here: http://www.kelvin.com/

------------------ Video ---------------------------

Here is a video series that I like to show in my physics class: The Mechanical Universe, made at the California Institute of Technology. The lectures and demos are by Caltech Professor David Goodstein. (Lots of fun!)
(Unfortunately, the El Rancho firewall blocks it, but you can watch the videos at home.)