Why did I not do this before? Ubuntu Linux Running on Virtual PC
I used to have an Ubuntu partition running on my old Dell. I used it for development from from time to time and I just enjoy using Linux/Unix systems, so it was always nice to have that partition to switch into when the need arose (How often was it to use wget? Pretty often.) When my Dell died and I got my new HP, I really didn't have any time set aside to set up a dual boot machine. I had client work hanging over my head and had been without a computer for something like three weeks so it was a desperate situation. There was no time for niceties. I had to toss the Adobe Creative Suite disc in there, watch that thing grind through its install; toss the MS Office 2007 disc in and watch it do the same; and then I had to go.
Fast forward to this week. With the release of Internet Explorer 8, I set up a new Virtual PC using the IE App Compat VHD (in English- the Internet Explorer Application Compatibility Testing Virtual Hard Drive.) While testing that promising browser (and it really is promising), I was struck by the thought of setting up a Linux instance on a Virtual PC. One quick Google search later I was presented with this:
Installing Ubuntu on Virtual PC for Windows Lovers
Which seemed promising 
Following the advice presented, I was able to set up Ubuntu pretty much without issue and I've been happily messing around, setting up the environment for my needs (installing Apache, Mysql and PHP5, Subversion, Wordpress, etc.,) ever since. Even running inside another OS, it's actually a reasonable experience and everything else is pretty seamless. There's also the added bonus of being able to switch back and forth between Linux and my Windows desktop, which allows me to keep up with the day-to-day while still hacking mad gibsons on the Linux side.
As an aside, while I'm comfortable on the command line and on Linux/Unix systems, I'm not all that great at anything web-centric beyond what you have access to in a shared environment, so it's kind of fun for me to actually build and configure a server. I normally don't get a chance to actually edit apache configuration files (instead I have to on .htaccess files,) so a lot of what goes on there is a learning experience for me. Being the unrepentant geek that I am: Learning Experience + Computers + Open Source Software = Good times.
Anyway, even if you're not looking to set up a server and are just curious about the Linux "experience" this is an easy way to go about getting a taste without putting your current system into danger. Try it, risk free!
What are you waiting for?