At work, I'm the lead developer of a rather large, complex web application which interacts with many different technologies (Asterisk, Freeswitch, Cisco routers, python, XML-RPC, JSON, Django--to name a few). A few days ago, while implementing a ban system, I bumped into an interesting problem that was not trivial to find a solution to. So, here it is :)
The web application I'm developing is a private portal which allows users to manage teleconference lines real time. Since all of our telephony services are free of charge, we often get callers onto certain teleconference lines who want to abuse services (think of those trolls on the internet, except over the phone). As you can probably imagine, without strict regulation & technology in place, telephone trolls could cause huge problems for normal users.