Hi there! Welcome to Exilian - please do look around the forums, and feel free to comment on anything you find interesting.
I had an idea for a possible architecture game, but I've no idea how practical or interesting it might be. It's a single player game: the player is a Master Mason (in modern terms, the architect or engineer) building a medieval cathedral. They have to manage the various supplies - stone, wood, etc. - to build the different parts of the cathedral, along with the workforce doing the construction. All this takes money, of course, and they need to keep sweet-talking the church authorities and wealthy citizens to pay for the work. If the funds run too low, work stops, and all the workers leave - then when more donations come in, it costs more to hire a new bunch of workers. Also, you can have random disruptions: part of the building collapses, or there's a famine or plague affecting the city. How does that sound?