What is your favorite "side project" band?

Without a doubt, my favorite side project band is Thee Silver Mt. Zion Memorial Orchestra & Tra-La-La Band which is a side project of a few members of Godspeed You! Black Emporer with many extra artists. I heard and got into A Silver Mt. Zion before I heard Godspeed, and thought for some reason that Godspeed was a metal band of some sort, then when I found out that A Silver Mt. Zion was a side project I actually gave them a listen and loved them as well.