I can't believe I've never heard of this. And I have a friend who works for the Points of Light Foundation.
http://www.usaweekend.com/diffday/index.html
I'll be out of town that weekend, so I can't partake in whatever is going on. But I'll be on the lookout next year.
Funny how it is the day after the stop-police-brutality day (i forget the name

). I wonder if any area makes a weekend of making a difference by making an effort to curb police brutality. PHA Shriner?