Neat! I actually took letterpress in school and loved it. The letterpress typeface archive was run by one ancient hippie who'd been doing it since before my parents were born and you could ask him "I'm looking for a typeface that says 'inspiring but cautious'" or whatever and he could find it for you in the back. Letterpress+lino printing+bookbinding was the coolest semester I ever took and I highly recommend anyone interested in design try it out at some point - same as anyone interested in illustration should try ink sketching sometime.
Other than that - I was doing a poster for the bike shop I help run and couldn't find any good grease smudges online, so I went out to my bike and rubbed my fingers on the chain and onto some paper and scanned it and was super happy with the results :P
I also hear America's national parks typeface has been released as a font!