Video Surfaces of GTA Online's Content Editor
Way back when GTA Online was shown for the first time all of four months ago, there was a promise of a content editor being added to the game. Apparently, that wait was just too much for some data miners, and they've managed to get the editor running in the most current build of the game.
Given the open world 'do anything' nature of GTA, the creator seems to be somewhat limited in this incarnation. Players are given the ability to create weapons, vehicles, props, spawnpoints, etc. for deathmatches and races. The promised ability to create your own casino heist isn't mentioned in the video.
It could just be the content creator that is in the current code is an older, outdated build. The video is still a nice glimpse of things to come and how the cam works... albeit, he can hack game code, but apparently a tripod or video capturing device is beyond his abilities.
The same data miner has also spelunked the recently released "Beach Bum" DLC, and found a motherload of audio files. The audio alludes to future DLC with sharks, spying, camera phone upgrades, racing for pink slips, and all the usual chaos we've come to expect from Rockstar.
No official word from Rockstar on when we can expect the content editor or next DLC pack, but I wouldn't be surprised if we get another by year's end.