We use Google Calendar to track our limousine bookings/and the stock Android calendar on our phones. I'm looking for an app that will allow us to have a customer initial/sign at the beginning of their tour, and then again at the end. Confirmation when they have gone over their alotted time so we can go back and bill them for the extra amount - while having something to dispute their claim that they didn't really go over - other than the driver's statement. It doesn't need to be anything fancy, just a kind've time-clock that they can initial from touch-screen phones. It would be great if from there, it could sync the total ride-time to their Google Calendar event, but that's not necessarily critical -- just so it would keep its' own database.