Timeneye Time Tracking is a time tracking and reporting web app meant to be extremely simple and usable even for the most recalcitrant user.
Timeneye can be used from the web (http://app.timeneye.com) or from the Android mobile app. An iOS version is currently in development.
Timeneye integrates with Basecamp, allowing users to track time directly from Basecamp commenting on their to-dos with the time spent on them.