This URL:
http://chart.apis.google.com/chart?cht=t&chtm=europe&chs=440×220&chd=s:az&chld=GBFR&chco=777777,00ff00,0000ff
Generates this:
Too easy for words! Venn diagrams:
http://chart.apis.google.com/chart?cht=v&chs=200×100&chd=t:100,80,80,30,40,20,10
More here.