I like that the OSI raised the WTFPL licence at a 2009 Board Meeting. I feel the outcome, 'Reject', is a loss for open source software - I'd love to see a programme with LICENCE.TXT containing that.

As snippyhollow pointed out above, the FSF recognizes it as a free license. http://www.gnu.org/licenses/license-list.html#WTFPL It's even GPL compatible!