The Big Bear Solar Observatory is operated by the New Jersey Institute of Technology.  Their newest solar telescope has a 1.6 meter clear aperture and is the largest aperture solar telescope in the world.  Tours are offered from 2-3pm on the 2nd and 4th Tuesdays of the month.  I love the stark whiteness of the building against the blue and green of its surroundings.

Links:      BBSO (tour info, webcams, latest images)