Had some thoughts today, thought I'd write them down:
Been looking at Google refine. Some of this is pretty obvious, but I'm thinking it would be pretty awesome to port this to use on a database backend. Basically, do the transforms on the data in the database, and, if you want, it will serialize it back out to a new table, or replace the existing one.
What would also be cool is a generalized report generator for Rails, possibly using AREL. You could do security by defining mandatory filters for tables, limiting the tables/columns, and other things. It could predict the time the report will take to run by using PostgreSQL's "explain" command.
Here's a collection of links that I have open. Just putting them here so I can close them :)