Last year, I posted about creating a standalone Lion USB installer thumb drive. This year, I update those instructions for Mountain Lion.
You'll need a copy of the OS X Mountain Lion installer. If you saved a copy when you first installed Mountain Lion, great. If not, you'll need to re-download it from the Mac App Store.
Launch the App Store and option-click the Purchases tab. An "Install" button should appear next to Mountain Lion. Click it to re-download the installer. You can use this option-click-Purchases trick to re-download any purchase, not just Mountain Lion.
Once the large multi-GB installe
