I want a work-time tracker that lights a bright LED every 5 minutes or so, and as long as I'm there and working I smash a button and the light goes off for another 5 minutes. Some algorithm tracks the times I have hit the button and displays how long I have been working on said task.
I'm picturing something fairly cheap, like a stop watch or 3 button kitchen timer. A LED, a few buttons, a LCD display, a AAA battery slot, and an internal timing circuit is all that's needed (and a case to hold it together).
This would basically be a stop watch that stops on its own if neglected, and I can imagine a few uses for it.