I've thrown around the term more and more lately, sometimes it results in blank stares, sometimes knowing chuckles, but more often than not, it results in stories. 

For the handful of you who aren't familiar with the term, here you go:

Guerilla Development is when software development has to occur under the radar, off the books, without approval of the powers that be.  This can happen for a variety of reasons... it could be a prototype or proof of concept for a demo to get buy in, it could be because it's needed and there's not the official time/budget for it.  Or it could be that the people in charge are dumb.

No matter what...  it's always an interesting/fun thing to do.

A few years ago, I worked in an organization that used employee id's and SSN's as your  username/password for all web apps.  If there was a need to perform an action - eg. timesheet approval - for someone else, their manager could pull their information, log in, and take care of it.  Other than the obvious problem of using sensitive information in such a trivial way, it also gave the entire development team this information on every past and present employee of the company and gave you a set of credentials that couldn't be changed.

To make things a little more secure, I worked with one of the network security guys to implement this crazy thing called LDAP using ActiveDirectory.  After a hours of tweaking over the span of a few weeks, the server was online and one application was tweaked to use it.  The application had no noticable changes, behaved the same way, and didn't have quite the same gaping security issue.

The day before the presentation, the Security Office sent a notice suggesting that using SSN for identification/security was A Bad Idea(tm), so we thought we'd be congratulated.  Five minutes into our presentation, we were shot down for ignoring the org chart and spending time on unauthorized projects.  Within a month, the network security left for a better job... and I started CaseySoftware fulltime.

What's your best Guerrila Development story?  Who have you had to fight?  Did you win?