I'm just going to post this up and not comment too much. PSP haxors have ported an Apple II emulator to the handheld, which means, I suppose, you can play Oregon Trail on the bus ("Wolves have eaten your mother!"). I posit that the number of possible PSP ports is infinite. I leave the proof of this as an exercise for the reader.
Next up? An Altair emulator for the PSP along with a punch card reader. We can only dream.
Apple II Portable for the PSP [PSPUpdates]