Santa and Santa's Little Helper
There is ambiguity in who actually discovered 2003 EL61. On MPC's List of Transneptunian Objects the location of discovery is listed as Sierra Nevada (07.03.2003 - 00:40:40 UT - Sierra Nevada Observatory, Granada, Spain). The object was discovered by Mike Brown's team on 28.12.2004, and therefore the nickname "Santa". You can read more about the subject on Mike Brown's website
Brown's team discovered on January 26, 2005, that 2003 EL61 has a little moon, "Rudolph". On November 07, 2005, they found another satellite. In September 2008 Haumea was given its name and the moons were named Hi'iaka and Namaka.
Image: Mike Brown/Caltech