I'm sorry if this isn't super coherent. I just got back from participating in the semiannual PennApps hackathon at the University of Pennsylvania this weekend. (I didn't get very much sleep.) I worked with Tess Rinearson and Nick Meyer to create Grassroutes, and we ended up winning second place. You can watch demos here; we start at about 29:05, and Tess did a great job with it.
Grassroutes was born out of an observation that we had made about SOPA: everywhere you go on the internet, there is a call to action to call/email/Facebook/Twitter/snail mail your people in Congress to make them see how evil SOPA is. However, this is because many of the people who don't like SOPA are programmers, so they have no problem rolling their own widget to put on their site to exhort you to go do their bidding. Grassroutes makes it easy to create an embedable widget that you can place on your site that will tell your visitors to contact their Congresspeople to support your cause, so that anyone can do it. (You just need to know enough to copy and paste HTML.)
We use the Twilio API for in-browser calling, we use the Maxmind ruby gem to go from IP->zip code, and the SunLight Labs Congress dataset to go from zip code->elected officials. (Every widget is personalized for the viewer with their elected officials based on where they're from.)
Check it out at grassroutes.us.