This may just be the biggest single giveaway we've held on Engadget yet. We dare you to resist the tempting lure of an 11-inch MacBook Air with 4GB RAM and 128GB hard drive, capable of running Mac OS X and Windows 7! With graduation season upon us, our friends at Parallels are hooking you up with the best senior gift that you could possibly receive. So what's this software all about? Essentially, it allows you to run Windows and OS X apps side-by-side on your Mac without rebooting -- that way, you'll get the best of both worlds. The MacBook Air will come pre-loaded with
