I've set up a few tags, but would love to find more uses :P
I have one tag on each side of my door - when I leave Tasker turns off wifi, enables 4G, and says "Have a nice day Jens". When I come back, it turns WiFi on, 4G off, and sets media/notifications/volume to loudest, vibrate on, and says "Welcome home Jens". (corny, but it puts a huge smile on my face).
I also have an NFC keychain that I carry around - if I go into class or a meeting or a movie I tap the keychain and it turns my phone onto silent. Tap it again and it puts everything back to the loudest setting.
If I end up dating someone (lol, this idea will never get used) when I tap the tag near my bed that does waking up stuff (volume back up, launches Currents) I'd have it send a text to my significant other saying "Good morning
The most annoying thing is having to unlock my phone before being able to use NFC -_-