bits manipulation (C)

I'm an autodidact and I have programmed in C for one year now, but never studied this topic. Apart from operating systems or embedded systems, when do we need to manipulate bits in 21st century ? If you could give some examples...

>>11
Keep in mind that I was being rather sarcastic; mplayer is really only a good example of what to do to make your program as unreadable as possible to people that don't know every minute detail of the C99 spec. I looked at it for the interface to the binary Real video codecs (and demuxing from mkv/rmvb), and I had to make test programs to figure out what some lines of code actually did (do you know out what val -= (val>>31)|1; does without compiling it?) And you have to wonder about the completely insane indentation, where an inner block is randomly indented further, less than, or equal to the outer block, depending on the phase of the moon in Germany when the code was written.