It's a 5k course and you can walk or run it. Now, since it's a color run, that means runners will be showered with colored powder, made of food-grade corn starch, at stations along the run. I think usually it's one color station every mile or so. So five miles, five stations, five colors.
For many Catholics, part of celebrating St. Patrick's Day is enjoying corned beef and cabbage. When St. Patrick's Day falls on a Friday in Lent that's an issue.