Urusei Yatsura is a complex Japanese pun that is probably worth explaining, since Rumiko is tremendously fond of puns, and liberally sprinkles her work with them (as do most Japanese writers--puns are a linchpin of Japanese humor).

Japanese is a wonderful language to pun in, since the characters have pictorial meanings in addition to their readings. In the case of 'Urusei Yatsura', the pun works like this: 'urusai', meaning 'noisy', or 'shut up', is usually written phonetically in the hiragana character set. Takahashi substitutes the kanji (pictographic character) 'sei', meaning 'star or planet'. This character is used when naming planets--eg. Mars is called 'Kasei' in Japanese (the 'ka' meaning 'fire'). 'Yatsura' is a somewhat low-class term meaning 'rabble' or perhaps 'group of obnoxious people'.
So the first level meaning is simply 'Planet Uru Rogues'. Layering on the obvious 'urusai' implication, the second level meaning is more like 'Those Annoying/Obnoxious Aliens from Planet Uru'.

All of these meanings are more are immediately perceived by the Japanese when they read the title--alas, we can only feel a fraction of that impact. But it does highlight the difficulties faced by translators of Takahashi's works--and Japanese comics in general.