The Dwarf Planet 2003 UB313 (you know, the one that's bigger than Pluto) now has an official name, and it's not Xena. The IAU, which names solar system bodies, as well as demoting planets, has given it the name Eris. It has been named after the Greek goddess of discord and strife. That's very appropriate given the strife caused since it's discovery which eventually resulted in a change of the definition of a planet, and Pluto's ultimate demotion to dwarf planet status!
More details at the Bad Astronomy Blog .