It's a real holiday. Apparently National Superheros Day was started on April 28, 1995 by a group of Marvel Comics employees. Celebrate the "superheros" in your life this year by giving them doughnuts. Krispy Kreme is making it cheap to do by offering a coupon at http://www.heroappreciationday.com/ that you can print out and bring in to a participating Krispy Kreme location to redeem for a free dozen original glazed doughnuts with the purchase of a dozen doughnuts.
Then don your cape and hand them out to all the heroes you encounter from day to day. The offer is good on Sunday (April 28) only, while supplies last.