Unity project cloning the classic Pong game.
Move Player 1 with the W/A keys. Move Player 2 with the Up/Down keys. ESC to pause.
I spent more time on this than one might think simply cloning the most basic game possible. I wanted to add fun features like post processing, music, and sound/UI/graphical effects that I don't ordinarily get to use in my daily work.
I spent maybe an hour and a half adding the core gameplay mechanics, and at least another hour trying to tune the feel of the ball and paddle movement. Perhaps another 2 hours was spent attempting to setup a cleaner UI management system before giving in to temptation and going with something far simpler and uglier. There may still be traces of the other system in the code.
Another handful of hours were spent dressing up the effects and adding fun features like the pause menu. I also had to spend about an hour chasing down an issue that appeared only in the build which was not occurring in the Editor.
All told, I may have spent up to a full workday's worth of time on this, but I'm very happy with the end result. That said, given the justification to spend more time on it, I'd love to make the UI and asset management resemble something closer to what I normally implement, which I'd be happy to discuss with anyone interested.