Trusty Tahr is the codename for Ubuntu 14.04 LTS which is scheduled to be released in April 2014.
Brief Release schedule as follows
Alpha 1 -- December 19th (for flavours)
Alpha 2 – January 23rd (for flavours)
Beta 1 – February 27th (for flavours)
Final Beta – March 27th
Release Candidate – April 10th
With the final release scheduled for:
Ubuntu 14.04 LTS – April 17th
