An idea. I'll try to be short.
Wikipedia has a lot of information, and it is heavily crosslinked. But it's not indexed. I mean an index of people, and index of places and an index of things. And events. And countries. And lakes. And whatever. Each index is a table (in database terms), with a few required fields. You could the add a page (or a part of it) to an index (or more indexes) by specifying theese required fields of an index (probably in the wiki source). The MediaWiki software would create real database tables based on this information.
Using this you could look up things/people that happened, borned, died or whatever on a given day. Or things that happened in Tokyo, or in 1923, and put that on a Google Map. Look at Wikipedia as an intelligent "who's who" (searching not only by name). Or list books or movies that have wiki pages about them. Possibilities are quite broad. Look up pages that are in multiple indexes, "events" and "presidents of the world" for example.
"indexers" would be wikipedians who index things. Make and index, like "countries" or "operating systems" or "mysteries". And then collect things into that index. And specify the attributes (database fields) of that index. There are pages like this, I know, for database systems for example, but you see this is a different level. You could create an index of abbreviations for example...
(I don't have much time to discuss it, but if anyone finds it worth working on, please let me know. Later I might join in. Have a nice day.)