After wasting hours of time daily surfing time-draining websites, I wanted a mechanism to stop myself from doing so that I actually wouldn't immediately disable. I needed a gentle reminder to stay on-task, so I decided to try to get my Pebble to vibrate while I slacked. I ended up accomplishing this in possibly the crudest way possible; sending SMS to my phone at regular (15-second) intervals until I navigated away. Thought others might find it useful. Pretty much my first attempt at any sort of web coding, so be gentle.
https://chrome.google.com/webstore/detail/nag/jnplobmicjmincpjonhajdhcaeimbakn?hl=en-US&gl=US