Cary Walkin, an accountant in Toronto, knows a thing or two about Excel. So great is his expertise that he was able to create a full-fledged RPG inside of its scripting environment, called Arena.Xlsm. I couldn't get it to run in LibreOffice, but it sounds like it's very featurful and fun, provided that you're willing to use Microsoft products:
* Random enemies: Over 2000 possible enemies with different AI abilities.
* Random items: 39 item modifiers result in over 1000 possible item combinations and attributes.
* An interesting story with 4 different endings depending on how the player has played the game.
* 8 boss encounters, each with their own tactics.
* 4 pre-programmed arenas followed by procedurally generated arenas. Each play-through has its own challenges.
* 31 Spells. There are many different strategies for success.
* 15 Unique items. Unique items have special properties and can only drop from specific enemies.
* 36 Achievements.
* This is all in a Microsoft Excel workbook.