They're into astronomy.
Google has joined up to be a colaborator on the Large Synoptic Survey Telescope (LSST). Google's specialty in this matter is to help organize all the data that the LSST will be generating, which is a lot given that the LSST will be using a 3-billion pixel camera to take series of which each exposure will last 15 seconds, giving somewhere around 30 thousand gigabytes of data a night! A scale model of the camera is shown at right. Each one of the little squares is an individual CCD, the combined image of each, producing the full mosaic.
And here I was thinking I was doing well with my nice new 250 gig I got for Christmas.
All this is still dwarfed by the realization that the survey mission of the LSST will be running for a decade, beginning in 2013. Another nifty feature is that it will be able to image the entire sky in just three days. Having such closely spaced images will help to pick out things that change their position or appearance on the order of days. This primarily means things like asteroids and comets, but could also be used for some longer period variable stars.