On March 7th, Dr. Jeff Morgan hosted another Houston Area Calculus Teachers' workshop at the University of Houston. The guest speaker was Dr. Mike May, S.J. of St. Louis University Math Department.  He presented an excellent workshop on GeoGebra, a free, cross-platform program that makes animations and applets for graphing, geometry, statistics and more.  Below are a few of my early attempts.  I will be adding more as I get time.  

Lines	Algebra I : a demonstration on converting from Slope-Intercept to Standard form
Incenter	Geometry: a demonstration of the incenter of a triangle
Circumcenter	Geometry: a demonstation of the circumcenter of a triangle
Parabola	Algebra II: a demonstration of transformations on a parabola
Conics	Algebra II: A demonstration of conics in standard form
Conics2	Algebra II: same as above but with modifications requested by Mr. Kiecke :)
Rotated conics	Algebra II or PreCalculus:  same as above except with the edition of the xy term to allow rotations a x² + b x y + c y² + d x + e y + f = 0
Sine	PreCalculus: a demonstration on transformations of the sine graph
Cardioid or Limacon	PreCalculus: a demonstration about the relationship between a and b in r = a + b sin t
Roses	PreCalculus: a demonstration about the relationship between n and the number of pedals to the rose
Taylor for Sine	Calculus: a demonstration of Taylor polynomial approximations
	More to come soon......
GeoGebra website	Home page of GeoGebra where you can download this program.
Mathplotter	A web site with many interactive demonstrations including many made with GeoGebra (mathplotter.lawrenceville.org)