The genius lads and ladies over at NASA's Jet Propulsion Laboratory have been so kind as to set up a webcam in their state-of-the-art clean room, the very same one where they're assembling the Curiosity Mars rover. Tonight? They're working on the wheels.
The Curiosity rover is one beefy vehicle, weighing in at nearly 2,000 pounds with six wheels to cart around its bulk; compared to the Spirit and Opportunity rovers before it, it's nearly twice as long and five times as heavy.
If all goes well, Curiosity will touch down on Mars toward the end of 2012 (August is the target, right now), where it will roam across the Martian landscape, drill into it, and analyze soil samples.
As mentioned, JPL has set up a Ustream where you can watch the rover crew work — typically during the day and into the evening — or you can poke around the archived video there to see how Curiosity progressed step-by-step.