Many "applets" which simulate simple lab experiments and demonstrations can be found at the site www.explorescience.com, especially in the Mechanics section.  One of these is the simple harmonic oscillator.

Another collection of applets can be found here, including one for the harmonic oscillator showing the relation between simple harmonic motion and uniform circular motion, and also one for the ideal gas illustrating PV=NkT .

The Tacoma Narrows Bridge disaster is described in many places on the web.  For example, these.  Here's a video.