If you're eager to try Microsoft's Windows 10 technical preview on a PC, you'll either need to mess with your existing machine, use a spare you don't mind borking or run it on a virtual machine like VMware. Mac users on OS X (including Yosemite) have a couple of options including Boot Camp, but they now have one more: Parallels 10. Using the latest build, you can download Windows 10 directly from the desktop, then run it in a virtual machine alongside your Mac stuff. That'll let you scope the incoming OS and its resurrected Start menu, Cortana support, new browser and Office Preview for Windows 10. You'll also get direct access to your iCloud and iPhone library and be able to share files, text and pictures from Windows. There is one serious gotcha: you'll have to pay a steep $80 for Parallels 10, or $40 to upgrade.