Reports: Ad-hoc database queries
This report, created by The Open University, lets Administrators set up arbitrary SQL select queries that anyone with the appropriate permissions can then run. Reports can be set to be runnable on-demand, or automatically run weekly or monthly.
The results are displayed as a fairly plain HTML table, and can also be downloaded as CSV.
The idea is that this lets you quicly set up ad-hoc reports, without having to create a whole new admin report plugin.