OK, I admit, when I first saw this I was skeptical as to how it could be used, but the more I think about it, the more I like the idea. The site http://rss2pdf.com/ will take any RSS feed or OPML file and instantly turn it into a PDF.
One way I thought this would be helpful is for sending RSS feeds to people who don't "Get RSS." People like my boss. Anyone can open and print a PDF, eh? Plus you can archive feeds on your hard drive easily for offline reading.
It's in beta (what isn't?) but it seems to work well. I'd like to see some formatting options so you could create your own newspaper or magazine from your favorite RSS feeds. Also, It would be great to have a scheduler that would create PDFs and store them on your hard drive automatically for plane trips, train trips, etc.
I'm sure I will find some other cool uses for it, let's hope it stays around and stays free.