Once a week, the Foursquare design team has an hour-long meeting. The first half is presentations from a couple of designers on what they've been working on recently, and the second half is a 30-minute design exercise. This past week it was my turn to lead the exercise.
I printed a bunch of copies of an empty Pebble watch, and asked people to design a watch face of their own. The only requirement was that you be able to tell the time by looking at it. Here's what everyone came up with: