The diurnal mean of the energy emitted is equal to the energy received (otherwise the oceans would quickly boil away).

The difference is that the energy emitted has a much higher entropy than the energy received: solar energy comes from a source with a temperature around 6000 K, i.e. low entropy, Earth emits the same amount of energy at a temperature of around 300 K, i.e. high entropy.

Hence, it is much harder to get any useful work from the emitted than from the received energy.

Name a program you could make in C or perl that you know well

Actually I think you should take this a step further, not just taking a program you could write, but one you have written already. This turns the exercise from a programming-from-scratch to a porting one: All logical problems were solved when you wrote the original version. Now you can concentrate on the details of the new language/framework/whatever.

I keep all my notes, random thoughts, links, etc. in one huge (mostly) plain text document, switching to a new every January, 1st: notepad.2009, notepad.2010, notepad.2011 etc.

I have been using this system for more than 10 years now, and it works very well: Switching to a new file at each new year avoids having the file growing too large, while still keeping plain text searching easy: it is in general no problem remembering which year I did this or that.

Merlin Mann blogged about a similar system some years ago over at http://www.43folders.com/2005/08/17/life-inside-one-big-text-file ... I think it was also discussed on slashdot back then, but cannot find the thread right now.

imagine a beowolf cluster of these... ... ooops - wrong decade - sorry!

... how did the battery manage to get a screwdriver in its hand?