O'Day is a prominent lunar impact crater that is located on the far side of the Moon. It is intruding into the northwestern edge of Mare Ingenii, and the rim is lower on that side. To the northwest is the crater pair of Holetschek and Sierpinski.

George O'Day collaborated with Uffa Fox, in 1956, on designing a 17' fiberglass daysailer sailboat, with a 6' beam, a large cockpit, enclosed centerboard, aluminum mast and boom, ability to fly a jib and/or a spinnaker, be easily trailered, and when moored not capsize when filled with rainwater. Since 1957 the boat was built and sold by O'Day's company and later various other builders, such as Spindrift, Precision Boat Works, McLaughlin Boat Works, and Sunfish/Laser Inc. Today the boat is built by Cape Cod Shipbuilding Co.