Founded in 1980, the Pan-Mass Challenge (PMC) is an annual bike-a-thon that raises more money for charity than any other single event in the country. The PMC donates 100% of every rider-raised dollar for cancer research and treatment at Dana-Farber Cancer Institute, a total of $900 million to date. Always held the first weekend in August, the PMC offers a dozen cycling routes that range from 25 miles in one day to 210 miles in two days. Registration opens in early January!