As a celebration of my 60th year on this planet I've decided to race 1 mile for every month I've been alive: 60 * 12 = 720 - simple.
I've set some rules: the miles must be off-road, so road race don't count, they must be part of a recognised race with a mass start and a pre-defined distance (barring getting lost!), so mountain marathons don't count, and the races must be 10 miles or more, so the Shropshire summer series doesn't count.