The Plum Book of Presidential Appointments
I never seem to know exactly how many positions a president can appoint. Well here is the answer (or here if you want easier to upload chapters). This book is great as you can show the kids, literally, how many jobs Obama must appoint. Since ambassadors are one job covered in textbooks, I will show my students this page and then this page so they can see the Executive Office of the president and here for the entire cabinet. Go here for the legend. You can read an article on this process here or read how political appointees like to "borrow in" at the end of an administration and end up in high level civil servant jobs.