Any Interesting Glitzy Yet Reasonably Complex Demos Out There?

Hi,

I am looking for a reasonably complex, Open Source, Ruby on Rails DEMO.

Preferentially it should have a fairly complex database schema, and
perform a reasonable mix of inserts/updates/selects. Ideally I would be
able to script a web load to test the impact of database performance.

The demo should also look glitzy so when it's showed to end users, they
would be reasonably wowed.

Ideally it would be a web application, but other application ideas that
could benefit from a database capable of running in the 1 million-plus
transactions per second range would be super useful.

So do you know of any good demos to port to a new highly-scalable SQL
database?

Thanks in advance,

Bob