I don't have cats at my house but over at my cousin's we have 2 an they are not to get anywhere near the computers. I have a dog an she isn't allowed to touch my computers either.
My kittie used to try it when I used my desktop (or he'd get up there on his one and "type", so the desk chair had to be moved away). Now that I have a laptop he doesn't try anything.
I don't know what it is with cats, but they seems to insist upon walking on the keyboard while you're typing! They have no interest in it, otherwise. It's funny and cute, but I can't let them all up on my keyboard! Sorry kitty.
We don't have one, but my parents' kitty would sit on their lap and swat at the keys when they'd try to type. I'd get the weirdest emails from them. lol