You can do that with a live CD, which will not disturb your current Windows installation in any way, since it boots and runs from the CD.
You can download and ISO image, then burn it to CD.
Mepis is my current favorite, but there are many others.
I keep a Knoppix and a PCLinuxOS on me at my support job and copies for home/travel.
The Live discs have come in handy for hardware ID and testing on quite a few Dells. They did a better job of hardware detection than the Dell Diagnostic discs most of the time.
The live feature is the best part to me since it doesn’t change anything on Windows.
I have even given a few away as gifts for people to try and they are amazed at the friendliness and reliabilty.
Any Java OS’s out there yet?