Linux on Mac

I'm posting this thread here because I'm not sure where else it would go.

I'm a life time Mac user but now that I have a taste of OS X and Windows on my MBP, I want to try out Linux just to see what it's like. However, I've never installed Linux myself or used it extensively and so I'm thoroughly confused by all the different distros that are available. I'm looking for suggestions in terms of what kind of Linux is good for me to start out with. I don't plan to make it my primary OS nor do I plan to spend a lot of time in it but I do want to dabble in it. What I want is something that is free, relatively easy to install on a Mac, and pretty representative of all the different flavors of Linux that are out there. I am fairly comfortable in command line on Mac but I'd rather not have to deal with a bunch of messy command line prompts to install and use it. Any suggestions? Alternatively, is there a good website/forum that I can go to that is helpful and specific to Linux on Macs?

 

Is Linux through Parallels going to be really slow?
It sounds really awkward to have to go through that extra layer.