A virtual sign-making tool that happens to have a game attached to it.  I like how individual sign components get incrementally cheaper as you take turns buying them, and the animations are incredibly satisfying – though certainly moreso when you're beating Filthy Burger instead of the other way around, which feels very reliant on luck sometimes.  (Or maybe I'm just bad at this exact sort of strategy gaming?  Nah, it's definitely the RNG.)