University of St. Andrews (UK)
University of St. Andrews: Conchoid of De Sluze Applet
Zoom in and out, and add evolutes, involutes, etc.
University of St. Andrews (UK)
University of St. Andrews: Astroid
This site from the University of St. Andrews allows you to zoom in/out and add evolutes, involutes, etc.
University of St. Andrews (UK)
University of St. Andrews: Hypocycloid
Shows the graph and the parametric cartesian equation. The site also includes links to graphs of related curves and definitions of the associated curves.