When I wrote about Just Cause 2 Multiplayer a few weeks ago, it felt like a world in wait of a game that was worthy of it. Its players might still be the ones to build that game. With the release of version 0.1.3, JC2MP's creators of highlighted a community server: Jman100's Freeroam Construction Sandbox. It lets players build their own houses, towns, ramps and other contraptions within Just Cause 2's Panau, by spawning and positioning props on the multiplayer server. There's a trailer below.
Servers have trailers now? What a world we live in.
Just Cause 2 was originally a singleplayer-only game, but JC2MP allows hundreds of people to pile on a single server and play around with its physics toybox. You can spawn boats, planes and cars, race against your fellow players, take part in destruction derbies, or more likely, make your own fun by harrassing one another and triggering lots of explosions.
As part of that make-your-own-fun ethos, the mod adds the ability for the savvy to create their own LUA scripts and define their own game modes. That's presumably what JMan100 has done in order to create this fiddly-looking build mode.
Given that the original game not only had no multiplayer, but no mod tools, it's incredible what people are making within it. Many mods have benefitted similarly from adding LUA scripting - Garry's Mod is the prime example.