Now this is completely awesome–an ASCII fluid dynamics simulator! The project was an entry by Yusuke Endoh to the International Obfuscated C Code Contest (or IOCCC) back in 2012 (which in itself is a fascinating thing). Just watch the text fluid in action.
If you want more information about it, or want to compile and try it for yourself, check the information page of the IOCCC project over here, or check out the home page of the IOCCC for more strange projects like this.