No future Astros, only former Astros with birthdays today ~
3B Steve Hertz (67)
Hertz appeared in 5 games for the Colt 45's in 1964 and those 5 games constituted his entire major league career. He was unable to get that elusive hit in the majors. Thankfully, he went on to have a very successful career coaching for Miami Dade College. As an interesting side note, in 2007 he managed the Tel Aviv Lightning in the Israel Baseball League.
RHP Don Lee (78)
Acquired in a trade with the Angels for OF Al Spangler, Lee pitched for the Astros in 1965 and 1966. In 16 games, he was 2-0 with a 2.77 ERA and a 1.231 WHIP.
RHP Gary Majewski (32)
A Houston native, Majewski only appeared in 2 games for Houston at the end of his career. Since it's his birthday, I will be charitable and not post the results of those 2 appearances. Majewski had his most effective season in 2005 for the Nationals, going 4-4 in 79 appearances with a 2.93 ERA and a 1.360 WHIP.