I have had an NFC capable phone for a year now and just decided to start playing with the technology. My first simple hack is NFC tagging my notebook.
I ordered some tags and installed the NFC Task Launcher app. After playing around with making NFC business cards and a tag for my bedside table which toggles the ringer on and off, I tried to come up with something really useful.
I use Evernote continuously but for times when a pen and paper is just better than a touch screen, I have a nice leather bound notebook I like for sketching and taking notes. Having been envying the Moleskin for Evernote notebooks that only work with the iOS version of evernote, I figured I could at least party upgrade my notebook. By adding a tag to the notebook, now I only have to touch the phone to the book to create a new note and then take a picture of the page.