Hints&tips for a real Egypt experience, out of the beaten tracks (Cairo)

Hi, I'll be visiting Egypt 25Dec-8Jan with a girl friend on a backpack self made tour. We'd like to hear from you on suggestions for accomodations/ restaurants/ going out in Cairo and Assuan, out of the usual tourists routes. Will it be possible to do some wind-surfing (with a wetsuit maybe?). Are Xmas and NewYears celebrated there or which are the dates of the muslim calendar this year? Thank you! Lella