You can download and run Ubuntu as a Live Distro from a USB memory-stick. Plug it in, boot from USB, instant Ubuntu. It's not a VM, but it's quick, easy, and needn't affect your existing system.
You can download and run Ubuntu as a Live Distro from a USB memory-stick. Plug it in, boot from USB, instant Ubuntu. It's not a VM, but it's quick, easy, and needn't affect your existing system.