An article in Scientific American, June 1976, vol. 234, no. 6, p. 21 "The
Choice of Voting Systems" by Richard G. Niemi and William H. Riker shows
various voting paradoxes in legislative voting (voting on bills).
It should be read by everyone to get some understanding of the problems in
groups voting for choices.
Especially interesting is an example showing the conflicting results between
the Condorcet, Borda and Copeland voting methods.