A terrain generator. It generates terrain: mountains, oceans, and plains.
Another terrain generator. It generates grass, water, and beaches.
A list of keywords from across programming languages.
A playable piano keyboard.
A list of jokes.
A generator of random coordinates for OpenStreetMap, and a convertor between OpenStreetMap URLs and Google Maps URLs.
A text generator which can produce output text resembling the input text. It uses, and is named for, Markov chains.
A page much like this one.