Utilizing just Excel and VBA script, this is an amazing example as to just how far Excel can really go. It then grew to incorporate computer opponents so a single player could play a four person game of Monopoly by themselves. It began as a way to come up with new strategies for computer players but eventually morphed into a four player board game of Monopoly. This simulation of the class board game Monopoly is just one example of how far Excel can go. There are even role playing games, board games, maze crawlers, it is quite amazing just what excel can do. The following 2 images, one of a Missile Command style game and the other a Tower Defense game, were all created in Excel. It can be taken even farther and build the games right into Excel itself.
Rather than organize customers and accounts, you can organize map locations, health, damage, locations and other parameters that games must manage as well.
At least that is the extent many users get with Excel.