There's this awesome feature that comes with every minecraft version. It is hard to find but after you start up Minecraft look for the option "SinglePlayer".
Alright xD enough with the jokes. I appreciate your input but making a server specifically just for cannons wouldn't be valuable but to a select few groups of players. If you would like to play on a world you can start a singleplayer world in creative or if it's necessary I can upload a folder containing the necessary components for a local server that you can run on your own network with WorldEdit.