A friend/collegea of mine had a really cool idea about c-style comments. C-style comments are multi-line comments that start with /* and end with */. They can be used in C, C++, C#, PHP, Java and a other languages. When this friend debugged some code, he found himself switching some blocks of code on and off all the time. He came up with a solution to switch between two blocks of code by just removing or adding one character!
See for yourself at: http://blog.mycroes.nl/2009/04/magic-comments.html