A software (and optionally, hardware) project for automating the creation of offsite backups on flash drives. The idea is that you have a large-ish flash drive on your keyring; when you take your keys out of your pocket, plug the flash drive into the device. The specific use case is a hanging key holder with a RasPi inside of it. The files in the backup script are automatically encrypted and copied onto the flash drive. That way, if anything happens while you're out and about you have the latest and greatest copies of the files already with you.

MultiBootUSB is a cross platform* software/utility to create multi boot live Linux on a removable USB disk. It is similar to UNetbootin but many distros can be installed, provided you have enough space on the disk. MultiBootUSB also provides an option to uninstall distro(s) at any time, if you wish. Also supports persistent storage volumes for some live OSes. Can also uninstall live OSes that it's installed.

There must be only one partition on the flash drive in question, and it must be formatted (mine was formatted VFAT).

Software that you can copy onto a USB key and run from any Windows system without having to actually install it.