Visa on Arrival is dead easy. Complete this form (
http://kenyahighcom.org.uk/wp-conten...-for-Visas.pdf) before hand, and also the landing card they will give you on the plane. When you land, go to a VOA immigration desk, pay your US$50, and visa is issued. Usually luggage takes 30-40 minutes to come through, so you should be at the carousel by the time it starts to roll.
Visa officers are available whenever a flight lands.