In 2011, my friend Will Wilkinson put out an iPhone app called Everyday. It reminds you to take a photo every day, and it then stitches those into a video. That's it. You've all seen these "a photo a day" videos before—this makes them super easy to do, so you're more likely to actually do so.
I started everydaying in March of 2011, and I set a calendar reminder to put together a video in 3 years. Today is 3 years later.
You can get the app here: https://itunes.apple.com/us/app/everyday/id398081659?mt=8&uo=4&at=11l4U2