Well, the only real game I made (like, one that wasn't just pong or something), I made in a language called blitzbasic. It's the kind where you have to manually load and display each image, update frames, handle collision detetion yourself. Basically starting from scratch. Anyway the game is pretty long, with a boss and a bunch of different areas, and it took 3 weeks straight of sitting at my computer, drawing/coding/building level databases (I mean, like, only getting up for food, sleep, and bathroom breaks). It's got over 4,000 lines of code (without spacing!), and 11,510 words.
But, yeah, 3 weeks is the time it took (or maybe a month...it was a while ago, so I can't remember...definitely a month if you count testing for bugs).