Some wonderful animations that show the sine, cosine and tangent of angles on the unit circle.

Sine Box
http://www.ies.co.jp/math/java/trig/sinBox/sinBox.html

Cosine Box
http://www.ies.co.jp/math/java/trig/cosbox/cosbox.html

Tangent Box
http://www.ies.co.jp/math/java/trig/tanbox/tanbox.html

This animation from Lou Talman shows how a point moving around the unit circle generates the tangent function.
http://clem.mscd.edu/~talmanl/HTML/TangentCurve.html

This Quicktime animation from Lou Talman shows how the sine curve can be constructed from the definition of the sine function as the y-coordinate of a point on the unit circle.
http://clem.mscd.edu/~talmanl/HTML/SineCurve.html

Mad Minute activities are warm-up and review activies. This one reviews the exact trig rations. Drag in the stickies as visual aids.