I used to have a cd of Puppy Linux that I used just for that purpose. It boots from cd, so there's not even a disk that a potential bug can write to...so it can't really be hurt at all.
Nowadays there are lots of options (various lightweight Linux installations) along that path using PC-based VM software (I prefer VMWare) and your choice of guest OS.
I'm a bit of a techno-nerd, to me virtualization = super groovy