Covering numeric types more in depth could be interesting. It seems to surprise most people when they run into '0123' for octal or '123f' (or is that 'f123'?) for a float, '0xdeadbeef' for hex, or 'b123' for binary (is that right...? you see it so rarely I'm not sure without looking up some examples). And I'm sure there's more: surely people have come up with notations for quarternions, complex numbers, and more.