Other than the mixed up V, W, and Q keys I did this to one of those cheap and ghastly low-throw Dell keyboards that came with one of our computers and hooked it up to my boss' machine.

...After first writing a custom Windows keyboard layout using the MSKLC tool and installing it on his machine to make it actually type that way, too.

A more subtle variation might be to swap a user's period and comma keys and see how long it takes for that to piss them off.