Bits in 60 seconds
If you are programming you will get in contact with binary digits sooner or later, well known abbreviated as bits. Then it is good to know what is, how it works, and to be able to calculate them without using a calculator. At the latest when doing a website with HTML or CSS you will have do deal with hexadecimal codes.
In the Nirwana Software blog I have found a very smart and quick explaination done with a flipchart and an easy example. In 60 seconds you will know, and if you are still at school, tell your informatics teacher, because most of them can not explain that clear and that short, I swear!