Having a lot of free time can be a great problem because it is difficult to structure something that is not divided in small units. By having to-do-tasks, the time of which is not dependent on the person, the time is structured independently and the person can manage its time better. Having few things to do, the management becomes very difficult, because the self discipline has a very strong reaction: the time consumption of pleasent non productive tasks. In the long term, these will bring unpleasent results...
I am a clock collector. Not of material clocks, but software. I never use a clock on my linux box, because I prefer maximising the usable place of the monitor, but I like having several clocks installed on my machine.
Today I installed tbclock. Very nice!... It is a digital clock with a binary representation of time! The hours, minutes and seconds are presented in different colours in 6 bits per time unit. It has an aesthetic value, which is rare for digital clocks, and a magic outlook, because of the binary scheme (you have to think in order to find out what time it is).
Its page is here.