Quite a lot of simulations and inquiry activities. May need to be run on Firefox and IE since they require Java.
Boatloads of potentially useful simulations and animations.
Reminder that lab procedures need to cut the BS and get to the point.
Source for copying & pasting super&subscript Unicode characters so they look like exponents. Useful for headings.
The craziest. They should be ded.
A great set of resources and tips for using Wikipedia with your courses.
An activity that requires students to attempt to build a boat with the best Cost / Weight ratio in a limited amount of time. Nice introduction to modeling and classroom culture.