Just an idea, but if there is one LED that we can control, I would imagine this project:
—Replace this LED with IR LED (same kind that is used in TV remote), should be extremely low power consuming;
—Then come up with a little project that simulates TV remote presses for particulal TV by sending proper code sequences.
Now that can be used for example not only to check what child is currently watching on TV, but even actively Turn ON/OFF, switch channels and etc.
Alternatively, another project might be something like automatic change of sound volume on your TV, thus mantaining the same level—I’m extremely unhappy that volume on different cable fragments fluctuates, so significantly and there is nothing in TV sets that could perform automatic adjustment.