The soon to be retired, MobileMe service from Apple, has a beautiful login page with wispy particles floating about. There is a lot to love on this page and an unbelievable attention to detail.
Inspired by the login page and a wanting to tinker with canvas and particles I set out to recreate the wispy particle effect. You can see the progress I made at the following page: mobileme-particles
I'm happy with how it turned out but there are a few things that could be improved. For one, the movement in the original is less rigid with more twists and turns. Is a flocking algorithm being used? Also, the mouse interaction with the particles in the original is livelier and has a nice bounce back effect when the mouse moves away from the particles.
If you'd like to look at or use the code you can grab it on GitHub.
Learning about particle systems
There are quite a few places on the web to learn about simple particle systems. If you want to go a little further and add forces, I found the following two posts useful: