Warning! This post is very old and may contain information or opinions that are no longer valid or embarrassing.
Well, apart from the standard activities you can do in Sinai like snorkeling, hiking, sleeping on the mountain that God spoke in a way that God would never appreciate, sleeping on the beach and dodging police flashlights at night, watching the sunrise and seagulls, sleeping in an Internet cafe along side a stray dog, sleeping in a bar's toilet, getting your legs bruised and scratched in your first windsurfing lesson, seeing veiled women getting out of the mens room, entering a room where two people were getting laid or whatever freaking mad thing you can do in that town.
Just discovered my new favourite activity in Dahab.
Try ripping and bringing down Mubarak banners at 5am in the morning followed by throwing the banners in the middle of the street and jumping up and down on them, while people can clearly see you from a distance. Nothing beats the extreme Adrenaline rush followed by the instant satisfaction. You feel proud the next day when no one replaces those banners or tries to fix them back.