what's up?!

<em>Sorry if it's a trivial question, but when someone uses what's up as a greeting I have no idea what they want to hear. What are the possible answers and what does this question mean exactly?</em>

My best and unforgettable trip : Africa Overland - part one - the planning :) I still remember clearly how was that day when I made up my mind to travel to Africa. It was a cloudy and raining day of December, very stressful and challenging at work. I had to manage my tenth and last meeting, during which I should have to talk again in front of a bunch of bored and demanding doctors about an effective and pioneering drug. I felt apprehensive, although I was well prepared. I supposed I was worried as well as everyone had to make a speech. So that I crossed the fingers and prayed : " Please God, give me energy and power and I promise you : I will be a good housewife for almost one week !:) ". My last meeting was a success and I obtained my hoped achievement. While I was driving towards home, imagined of being far away, in a peaceful and wonderful place, without bosses, collegues and especially doctors and hospitals. I was shattered and needed a break. "...A desert. No one can reach me there! neither by phone! why not Africa? nature, animals, and desert. I could spend some weeks there." I immediately called my best friend, Michela, that lives in one of the most awful city of Italy, which Milan: pollution, traffic, freezing temperature during the winter, hot temperature during that summer and populated by restless people. " Michela! how is going!? It was a sunny and warm day in Milan, wasn't? " I knew the forecast for that day : 3 maximum degrees, fog and rain. " Elisa! come on! do not make fun of me! you know, I work more than ten hours a day and moreover it has been always raining for all the week !" " Ok Michy, listen to me: do you remember the american movie Thelma & Luise? Grab a bag and come with me. It will be not an on the road america trip but an incredible adventure overland through Africa!" and the adventure was already started. For the second part we will have to wait. :) thank you in advance for the corrections :)