Mozilla Labs is always coming out with interesting ideas and open-source projects.
First a few months ago I discovered Ubiquity !
Today I found two more projects :
Bespin started in January of this year
“Bespin is a Mozilla Labs experiment on how to build an extensible Web code editor using HTML 5 technology.”
Jetpack started more recently (this month) and is being coupled with Bespin for it’s development.
“In short, Jetpack is an API for allowing you to write Firefox add-ons using the web technologies you already know.”
I’ve barely touched Bespin and I haven’t had a chance to even check out the tutorials for Jetpack but I most assuredly will in the next few days and report back 
