A few technical points I've had to explain to fellow Brits on more than one occasion:
* No, the light switches in your U.S. motel room had not been installed upside down -- Up for on is standard in North America.
* No, the majority of electrical outlets have neither switches nor shutters, and no that does not mean that they are dangerous and that Americans are being electrocuted by the hundreds because of it.
* You will find both a hue and a saturation control for the color on the TV, not just the latter as in Britain.
* Yes, radio and TV stations really do use those "funny" call letters; they are an FCC requirement. As a general guide, stations east of the Mississippi have calls starting with W, those to west start with K, but there are exceptions.