Friday The 13th is a good subject for graffiti right? Well, surprisingly, I couldn't find more than just these images online, but perhaps there are others out there, I just haven't really found them. Check these out and learn how to draw your own graffiti, and maybe you can do some Jason Voorhees stuff.
Here are some graffiti resources for learning that you can use today.
Learn Graffiti Guide - A guide to learn graffiti in PDF form.
Spray Paint Art - Make money learning how to do serious spray paint art, beyond graffiti.
Amazon's Listing of Books - Amazon has a ton of books on graffiti, click here to find them as low as a penny each.