The common name for the UBB Developers' Network. UBBDev (http://www.ubbdev.com) is a community site for UBB.classic (formerly known as UBB) hackers - that is, people who modify the UBB to do good stuff, like have a calendar, or allow extra moderators. It is quite possibly the most famous and busiest UBB hacker community.
All hacks are publicly available so anyone can download them and use them on their forum.
UBBDev also offer services such as forum installation and upgrades, for the newer users amongst the UBB community.
UBBDev is also (unofficially) "staffed" by Infopop employees.