At work we have over 600 servers spread across many cities, so we don't use any 'fun' names. The name has a standard of including city/location, function and number. Not our choice, this was enforced by a previous manager a few years ago. Even though location and such is all tracked in an inventory database, it is a little helpful to know where a server is located/function without having to look it up. Long ago, when we only had 50-60 servers and a different manager, they did have names based on celestial bodies and sports teams (weird combo, I know). Now with virtualization the function part isn't really useful, so we'll probably have to come up with something new, but meh, that's a story for another day.
At home however, my machines are named after the Endless/characters from Sandman. Destruction for my gaming rig, my SANs are named Lucious and Destiny, my main (non gaming) PC is Morpheus, wife's PC is Desire, etc.. etc.. I try to match the function with the appropriately matching character.