I'd try to organize something like Community Wizard, financial watchdog software for the government sector, that Hamilton Technology had going on in the late 1990s before the department of justice confiscated it and destroyed the backup tapes.
"Fitts recalls how, back in days after she cleaned up Irangate, BCCI and HUD fraud scandals, the one thing that gave her the most hope for cleaning up government was emerging technology, particularly the Internet. Prior to the mid-1990's, being a government watchdog was impossibly difficult, so... Hamilton Securities, created a computer program called Community Wizard which gave the user powerful capabilities of assessing and vetting all kinds of financial data on government and corporate business, all in an easily understood format....
Community Wizard was a data wonk's dream, until 1997 when Department of Justice agents destroyed Fitts' office and computer files and left her with nothing. However, Fitts knows Community Wizard can be recreated and, like the proverbial phoenix, the Solari Network will rise in its place."
Grow the economy, save the world, and put some bounds on the financial fraud epidemic the United States is having.
UPDATE: For starters, this might be an enhancement to an existing wiki system, to incorporate markup that would allow spreadsheet formula-like functionality -- collaborative accounting with version controlling. I know, I know. Yeah right. Oh yeah? Why not.
For seconds, I might try refactoring sql-ledger with the strictures and a sane html templating system, and use this as a basis for another way to foster distributed accounting and try to steer some direction towards open source accounting systems, which currently are quite disappointing unfortunately. See (OT) Perl Open Source accounting packages? where lemming observed, pretty much, Accounting packages can be thought of as source control with money.
For thirds, I would tie the above in with cyclos, in my opinion the best, but still not entirely satisfactory (need to do more research on this) open source community currency tool. (Note: Cyclos is in java, not perl, IIRC.) And into the mix, nbarter, an idea I'm toying with for multidirectional barter, kind of like friendster with a virtual currency function.
Regarding problems with cyclos, my last notes from beyond money has something about "What needs to be done: Rewrite Strohalm's Cyclos open source software so that it matches the GSX specifications, specifically fixing major security holes, enabling intersystem trading and allowing businesses with multiple offices Price Dual card readers and related equipment." I am not sure if this has been "fixed," but this is the last thing I was looking into.
UPDATE 2: Twiki, done in perl, already has spreadsheet-like functionality, I discovered after checking around. Now, is it robust enough to do this kind of thing? I'm playing around with it to try and find out.
UPDATE 3: I was just kicked off the solari forum, for reasons I won't go into here; long story. The above "towards a new community wizard" link, which is really where it all started, now shows "guest" for all my posts, which were previously marked tphyahoo. Ouch
I still think the path I outlined is a good one, and continue to look into it, although it appears doing this as a joint venture with solari folks is now an avenue I will have to abandon. Despite being kicked off the forum, and uneasiness with some aspects of the "solari universe" I encourage everyone interested in this sort of thing to learn about what catherine fitts and the others associated with the project are doing.