CERN is an international organization whose purpose is to operate the world's largest particle physics laboratory. Go through the short quiz and build up your Dreevoo knowledge score.
TinEye is a great reverse image search online service, that can tell you where an image came from, find different sizes of the image and you can find out if someone is using your image without your permission.
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, generally an ocean or a large lake. Take this quiz and build up your Dreevoo score.
Antarctica is Earth's southernmost continent, containing the geographic South Pole. What else do you know about this vast ice and snow covered lands except that it can get really cold?
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.