While I no longer am working on the ObHack codebase (modifications I did to the original 2007 Oblige 2 code), Fritz has taken over maintenance of the code and we have just released Obhack 006.3:
http://samiam.org/slump
ObHack has a number of features not in to the Oblige 3 codebase, such as Deathmatch and CTF support (unlike Oblige, even single-player maps have some basic Deathmatch support, and there's even a mode which tries to make maps that are both good DM and single-player maps), Heretic support, and what not.
I hope people enjoy the code. Feel free to post suggested features or bugfixes here, but remember that Fritz, not myself, is maintaining the code.