There is no specific end date. The crowd sale will end once the necessary development has been completed.
How long has this crowd sale been going on for? And what's happening in six days? Here
http://www.icocountdown.com/ it says that in six days it will be time for the next price increase.
Every month the price increases on the sell walls on Bittrex - the crowdsale has been going since Zennet.
Here is the history of the project:
https://bitcointalk.org/index.php?topic=736447.0