Raphaël – a JavaScript library for creating vector images

Raphaël enables you to create geometric shapes / vector images in your web page without needing to know the syntax of Vector Markup Language (VML) or Scalable Vector Graphics (SVG). You can follow Raphaël on Twitter.

Sample code (example from website) shows how easy it is to work with.

// Creates canvas 320 × 200 at 10, 50
var paper = Raphael(10, 50, 320, 200);
// Creates circle at x = 50, y = 40, with radius 10
var circle = paper.circle(50, 40, 10);
// Sets the fill attribute of the circle to red (#f00)
circle.attr("fill", "#f00");
// Sets the stroke attribute of the circle to white (#fff)
circle.attr("stroke", "#fff");

Animation of the shapes created can also be done with it (e.g. circles into squares).