I once saw a "any key" key in one online shop which sells all kind of funny stuff for computers, like usb devices that keep ur coffee warm etc.
So it was a normal size red key, which of course said "Any"
Of course it wasn't of any use, but when u get angry u could just hit it over and over again. (I'm pretty sure u just attach it to ur keyboard by tape or something.)
I almost ordered one for my grandfather because he ain't so good with computers.