If that's news to you, get in line. You're not alone.
According to NationalDayCalendar.com, it's a time to "Honor all people with the name 'Joe'", or a variation of the name.
So since it's National Joe Day, let's celebrate the Texans' greatest Joe: cornerback Johnathan Joseph.
The Rock Hill, South Carolina native entered the NFL in 2006 as the first round pick of the Cincinnati Bengals. He's defended 159 passes as a pro, which is the most in the NFL for active players.
Joseph signed with the Texans in 2011, and he was one of the driving forces behind flipping what was the NFL's worst secondary in 2010 into one of the stronger ones in 2011 and since.