Schemer is an underrated, underexposed Google app that helps you plan and discover plans based on your location. It'll integrate with your contact list and display what's essentially a social to-do list, or "schemes," that might be interesting or fun to do.
For example, if there's a particular food truck that you've been dying to try, you can add it as a "Scheme" and keep track of your social bucket list. Schemer will also scrape other friends' schemes based on shared locations.
Each user profile displays some pretty useful info., like the top schemes accomplished by each person, how many people they've "inspired," and who their influential schemers are. You can also track popular schemes, visually, via maps if you're looking for a quick to-do list.
It's been awhile since Google last updated the app, but here's to hoping for continued support...or possibly even a future integration with Google Now.