CAMBRIDGE — Even though he dropped out, Microsoft co-founder Bill Gates went back to school. He visited the Massachusetts Institute of Technology this week as part of a three-day tour to five Universities across the country.

Gates wowed student and faculty with a speech about philanthropy called, "Giving Back: Finding the Best Way to Make a Difference." It is quite a change from programming computers.

Gates now has left his duties at Microsoft to focus on two large problems the world is facing: health and education, and certain populations are suffering more than others.

"There are health problems, sanitation problems government problems," Gates said. "All of those problems make life so much for difficult for the bottom two billion, versus particularly the richest one billion. These are really big things that we haven’t given enough attention too."

Gates is planning to discuss these issues with other schools, but he has a special relationship with MIT. He even joked around about how he retook a physics class here and had a really tough time with it. All the students seemed to know the professor he was referring too. Other professors were pleased Gates mentioned MIT’s contributions to the world.

"He has mentioned many times MIT’s technology are very useful to our society," said Professor Venkat Vummadi. "He has mentioned it many times with props in the interest of biology and vaccines."

Gates is using an endowment of $33.5 billion to bring vaccines and medication to developing countries. Children die at very high rates because no one makes enough malaria vaccines in Africa. Gates plans to supply the funds for pharmaceutical companies to mass produce vaccines, and safely store them so they wont go bad.

Gates is deadlocked on this new goal. He chose MIT and the other universities to speak to because they have similar goals. Now he will move onto the next school and then go back to his benevolent work for the world.

You can watch the whole CES keynote address here. Also Gizmodo has a better quality video than most.

Bill Gates put together a funny, fitting farewell video starring Matthew McConaughey, Brian Williams, Barack Obama, Hillary Clinton, Jay-Z, Bono, George Clooney, Al Gore and more.

In one scene, Gates cell phones Bono during a show and tries to get in the band. Bono says to Gates,”Yeah, I know, I know, but I can’t just replace The Edge because you got a high score in Guitar Hero.

The video and keynote were given in front of 4,000 people Sunday night at the Venetian Hotel’s Palazzo Ballroom in Las Vegas.

Not a bad start to CES this year.