AgileCards Lite

It doesn't get any simpler than this: Swipe to the Fibonacci number you're playing, or double-tap to return to 1. (Implements a modified Fibonacci sequence: 1, 2, 3, 5, 8, 13, 20, 40, 80.)
Although points are not the same as hours, we use our intuitive sense of "level of effort" to select a point value. Our team treats each point as a Gaussian distribution spanning (0.5 * point) hours to (2.0 * point) hours. Feels like half a day of work? It's probably a 5. Feels like a couple hours; it could be a 2 or a 3. Ultimately, the actual time required to release an hour of work (1 point) will be much more than an hour -- hence the value of points.
With consistent planning, we can begin to track a velocity measured by total points accomplished in a Sprint. And with a team velocity, we get predictable projections.
For now, it's just points... stay tuned for more!
(Why the "modified" Fibonacci sqeuence? Because, when we plan a story or task that spans more than 13 points, we are no longer working at a sufficient level of detail to imagine that we're planning well. By shifting to 20, 40, 80, we adopt points which communicate the "level of effort," but simultaneously acknowledge that these estimates need to be refined.)