Complex sentence: Over 100 students and off-campus supporters met on the campus of the University of Minnesota--home to one of the oldest secular student groups in the nation: the University of Minnesota Atheists and Humanists (recently renamed CASH) which was founded in 1990.
Split into simpler sentences: Over 100 students and off-campus supporters met on the campus of the University of Minnesota. The school was the home of one of the oldest secular student groups in the nation, the University of Minnesota Atheists and Humanists (recently renamed Campus Area Secular Humanists), which was founded in 1990.