Glad you asked ;) Here's an example of the upcoming toxiclibs 0021 release which will support dashing of arbitrary line strips (including arcs/splines etc.). This example also works with the current release, but the code can be simplified in future:

This method draws a series of 1pt elipses (dots) in the shape of an elipse.  Spacing between dots is not quite uniform.

1. float x;
2. float y;
3. void setup() {
4.   size(600,200);
5.   noLoop();
6.   //frameRate(1);
7.   x = width;
8.   y = height/2;
9. }
10. void draw(){
11.   for (int i = 0; i <= width;i++)
12.   {
13.     x = width - x-i;
14.     y = -((float)(height/2)/(width/2)) * sqrt((float)sq(width/2) - sq(x-((float)width/2)))+height/2;
15.     if (x <= 0) {x *= -1;}// y *= -1;}
16.     ellipse(x,y,1,1);  // dots are here
17.     ellipse(x,height-y,14,14);
18.     println(str(y));
19.   }
20. }