The NES port of my toy language SLORTH! is pretty good at this point. Trying to decide Apple ][ or C64 next... I have working A2s in my collection to run it on, but also I know the system ok already, and it's a reasonably system to run it on. Boring! I have a C64 too, but it doesn't have a power supply and it's never been powered on. I've never even spent much time emulating the C64, and know nothing about it's memory map, IO, or anything. It makes it seem exotic. :p