If you have a Windows Phone that can be Interop Unlocked like the Samsung ATIV S you do just about anything, including it appears porting features from Cortana to your handset.
WIndowsMania.pl reports that a hack is now available which will allow you to bring select features from Cortana, in this case Quiet Hours, to the Samsung ATIV S.
On their site they include a package of files and the procedure for activating it on your handset, but note you need a handset with full access to the file system, only available with Interop Unlocked devices, and also that the hack is optimised for Polish users at present.
Cortana is expected to roll out to UK and China soon, but will likely hit the rest of the world only in 2015.
Read more about it at WindowsMania.pl here.