1 - The deity some Unitarian Universalists claim to worship. Mostly used as a snarky answer to the question "So, just what do you Unitarians believe in anyway?" because it's a lot easier than giving the standard elevator speech.
2 - A one-string guitar. Somebody must have thought of this one at some time... see tritar.
Praise Unitar! He/she doth will have mercy upon the aging hippies of the world.