I think the whole, "It's like riding a bike" applies to more things than the average person would think.
Once you've learned to do something and can do it easily, or "off by heart", forgetting how to do it would probably be harder than learning in the first place. (Without a knock on the head)
I'm sure you must have seen someone doing something really skillful at one time, and thought to yourself. "Geez, I wonder how they learned how to do that."
I'm sure there is at least one thing that you thought that way about once, and now you can do it just as good, if not better than the person who you thought that about all those years/months/weeks ago.
Maybe mirc scripting perhaps?