Now that Nvidia has gone and launched its GeForce GTX 580 videocard and stolen back the single-GPU performance crown, the GPU maker thought it wise to release a new set of drivers, version 262.99.
Unless you own one of Nvidia's new flagship cards, it doesn't look like there's much point in downloading the 262.99 drivers, unless you simply want the latest software for the sake of having it. All that really appears to be new, according to the release notes (PDF), is support for the GTX 580 part. There aren't any performance improvements or features added specific to the 262.99 release, or if there is, Nvidia decided to keep mum about them.
In any event, if you went and grabbed a GTX 580 or just won't sleep soundly until you have the latest GeForce drivers, benefits be damned, you can download them here.