You can parachute, play tennis, and drive around the city robbing banks with your friends in the multiplayer mode of Grand Theft Auto V, which Rockstar showed off today.

GTAV comes out for PS3 and Xbox 360, and with it comes Grand Theft Auto Online, an online mode that lets you customize a character—hey, you can play as a woman! (like you could in GTAIV's online mode)—and wander around Los Santos with up to 15 other people. Today's video shows players doing all sorts of missions, buying apartments, and even creating their own scenarios to screw around in.

Grand Theft Auto Online won't be available at launch—it'll open up on October 1.

GameSpot's got more details in a big preview they published today, and the multiplayer mode seems ambitious as hell. Some details:

• There's a stock market, which won't be available at launch but will be insane whenever Rockstar does put it in. You can invest in a car manufacturer and then storm around the city destroying every one of their cars so they have to pump out more (and their stock increases accordingly). Wow.
• There's also a fascinating new take on spectator mode, GameSpot reports: you could be in your apartment and see a police car down below your window somewhere, turn on the TV, and watch one of your friends run-n-gun with cops in real time.
• "It'll be GTA Online; it's not part of GTA 5," Rockstar North president Leslie Benzies told CVG. "Obviously it's set in the GTA 5 engine, but it's going to grow and evolve into its own thing."
• When the multiplayer mode launches, it'll be accessible through your character select wheel: in addition to the main three characters, Michael, Trevor, and Franklin, you'll have a fourth option for multiplayer.
• GTA Online will initially cover the same terrain as the pseudo-California-based GTA V. But Rockstar is hinting that we'll be breaking those borders at some point. From the company's official description: "Grand Theft Auto Online … begins by sharing gameplay features, geography and mechanics with Grand Theft Auto V, but will continue to expand and evolve after its launch.."
• AI characters "will react to the urgency in your voice," CVG says. Whoa. And... "Suddenly, a Rockstar developer sat next to us starts chatting into his headset and his on-screen character does the same, lip-synching broadly in time."
• While GTA Online seems like it's mostly made for multiplayer, there'll be ways to solo at least some of it. According to Rockstar: "In Grand Theft Auto Online, players have the freedom to explore alone or with friends, work cooperatively to complete missions…"
• According to GameSpot's preview, Rockstar won't be offering GTA Online's mission-creator tools at launch. They'll be rolled out some time after Oct. 1

UPDATE: One line in Rockstar's official description of their GTA Online trailer led some readers to speculate that GTAO would be tied to an online pass: "Access to Grand Theft Auto Online is free with every retail copy of Grand Theft Auto V and launches on October 1st." Not so, a Rockstar spokseperson told Kotaku. There is no online pass or code required for activating GTAO. Just buy GTA V and it'll become available via GTA V's character wheel (the fourth of four slots) on the first of October.