How to make a sphere

My question was how to make a sphere? Some things seemed easy enough, but a sphere almost seemed impossible. You can't extrude a circle because that creates a cylinder and nothing else came to mind. After this video i learned about how you can use a circle tool and revolve it. By doing so, you allow the circle to create a sphere.

This is the video I used.f
http://www.youtube.com/watch?v=rv0HAUC8p6c

Also to lweanr from another friend, I used the help of my friend ashab. Ashab had managed to create a cylinder so I asked him how to make one. He lead me through the steps pf creating a triangle, and then revolving it. At the end of this project, I managed to lean how to make a sphere and a cylinder.0