Messenger bots I threw together to learn how to use nodeJS/JS and build something relatively useful. They are all hosted on heroku. Some great bot frameworks I've used are boot-bot and messenger-bot-- the former has more functionality, and is more friendly!
Excellent tutorial to building a bot and using all the appropriate tools to connect it to Facebook and host it.
Share information about free food (type/location) at Amherst College with this bot, and it'll blast everyone who's interacted with it with your message. You can also ask for any updates in the last 4 hours. Uses mongoose and a sandbox mLab account to store food info... (it doesn't delete it)