SUDAN

Money is the overriding interest of most Sudanese but they aren't rude or beggars - they'll earn their money. Just beware of being overcharged, it seems to be a national sport and you have to haggle them down to reasonable prices.
The bureaucracy is well developed and, as a foreigner, you need register with the Aliens Registration Office (I'm not sure they'd understand if you listed your home town as Mars!) and pay - the amount varies so choose where you register carefully.
The country is swelteringly hot and much of it is off-limits because of continuing skirmishing between the hardline Islamic government situated in the north and Christian guerillas in the south. The guerillas even have their own embassy in Ethiopia.
Visas costs $61 and are available in Addis Ababa - don't appear at the border without one as they'll just turn you back.
The language barrier may be frustrating but it isn't insurmountable and the people are generally very willing to help you.
Articles on Sudan:

KHARTOUM
Sweltering on the Nile.
PORT SUDAN
Deserts and decrepit ports.