Multiverse Crisis MUSH

MUD Connector - a good MU* listing site.
PennMUSH Community - for information about the MU*ing community across the Internet.
Wikipedia - An online encyclopedia you can edit. The admin often use this when researching characters we're unfamiliar with.
TV Tropes - a site like Wikipedia, except for common trends and patterns in fiction. Very good. Very long. And very likely to suck up time. In particular it often has short, highly coherent summaries for many series and movies.
Pokemon Champions MUSH and Pokesylum MUSH - The players of these MUSHes (same MUSH, rebooted, actually) have relocated here along with their characters. If you're looking for it, give us a try.
Altered Dimensions 3 MUX - Another online roleplaying community that was folded into Multiverse Crisis, with a highly diverse set of themes in and of itself.