No future Astros, but several former Astros with birthdays today ~
LF/1B Danny Walton (65)
Drafted by Houston in the tenth round in 1965, Walton appeared in two games for the Astros in 1968 and another 13 in 1977. In between, he got traded around quite a bit. He was a minor league stud (.278/.368/.499 with 238 home runs and 800 RBI in 1315 games over 14 minor league seasons), but that never quite translated into the majors. He had a lifetime major league line of .223/.309/.376.
LF Derrick May (44)
Originally drafted by the Cubs in the first round in 1986, May came to Houston in a trade with the Brewers in June of 1995. In 187 games for the Astros in 1995 and 1996, he hit .273/.342/.432.
RHP Mike Burns (34)
A 30th round draft pick by Houston, Burns pitched in 27 games for the Astros in 2005 before being selected off waivers by the Reds in November of that year. He had a 4.94 ERA and a 1.194 WHIP for Houston that season.
RHP Juan Gutierrez (29)
Originally signed by the Astros as a NDFA out of Venezuela in 2000, Gutierrez appeared in seven games for Houston in 2007 before being included in a trade to the Diamondbacks for Jose Valverde. In those seven games, he was 1-1 with a 5.91 ERA and a 1.453 WHIP. He is currently recovering from Tommy John surgery and was signed as a free agent by the Royals in December 2011.