There is a sticky on visas, Mark, but it does say Sharm, so Briar will probably forgive you!
If you are not leaving the Sinai or even just staying in Nuweiba, you will not need to purchase a visa. They stamp your passport with a "free" visa for up to two weeks, on arrival. Just write "Sinai Only" on the back of your landing card before you pass through passport control at Taba.
If you should be planning a visit to The Ras Mohammed National Park, which is way down south, or anywhere outside the Sinai, you should, by rights purchase a visa.
Any queries, send me a PM.