Officially, the character turns 74 this summer.
For me, traditionally I'd hit every local comic store in the area on this day. Alas this year, circumstances have prevented me from this. But I plan to watch the Justice League: Doom DVD movie and hitting a store or two on my way home. But, if you truly like what Superman represents and stands for... Do something honorable and decent. Help someone out. Hold a door for someone. Hide your road rage. Whatever. But in all honesty, try to be a better person, be a Superman. Happy Birthday Kal-el.