Untwelve.org has a yearly composition competition with the goal of promoting microtonal and xenharmonic music to new audiences. It’s an open competition with a cash prize, so if you are a musician you should get right on it…
22 July 2014—UnTwelve is happy to announce the 2014 edition of the Untwelve Microtonal Composition Competition. While you can start composing now, our submission engine will be accepting your entries on or before October 1st 2014. The competition will close at 11:59 pm Central Standard Time December 15th 2014. Monetary prize amounts to be announced at a future date.
Have a look at the competition announcement for more details.
Edit: The results from the 2014 Untwelve Composition Competition are in!