well if you are still looking...

there is M&M hobby center. they have an offroad track and a mini onroad track and a mini offroad track that is astro turf jumps on asphalt. right now the only racing is stock RC18R onroad and some 1/18 scale onroad sometimes, 1/12th 4 cell stock, open mod 1/18th+1/16th offroad. the dirt track will hopefully be rebuilt soon. they did have 1/10, MT and, 1/8 races but that was several months ago.

Mikes hobby shop is north of houston but has an awesome onroad track thats good for 1/10 and 1/8 and they convert a part of it into flat oval. they also have a covered offroad track thats hard clay and big enough for 1/8. they will soon be finishing and indoor carpet track for minis and 1/12th but not for a few months. they have some kind of race everyweekend.

there is another track called southside that i dont know anything about other that its on the east side of town and they do 1/8 offroad.

there is also a small dragracing scene starting up at houston motorsports park. the facility is actually for fullscale oval and eighth mile drag racing.

www.gcdragracing.com
www.houstonrc.com
www.thrc18.com these are three good sites to checkout for schedules

hope i helped.