There are 3 that I've found

On the 22nd, I'm looking at doing the Head for the Hills in Chappell Hill, about an hour drive:
http://www.wcrotaryclub.org/h4h/

Riverside Ride in Victoria, about 2 hour drive:
RiverSideRide.com

On the 23rd, the Bluebonnet Express in Waller:
Bluebonnet Express Ride

Along with the MS150 link big_heineken sent, look at:
Texbiker's calendar: Bike Riding Texas | Bicycling events, Texas | biking, TexasTexbiker.net

and

Texas Gran Fondo CalendarTexas Bike Expo CalendarTexas Century Cycling CalendarTexas Cycle Tours CalendarTexas Ultra Cycling Calendar

and

Upcoming Rides - Bike Barn - Houston, Texas:

and

for some outside of Houston options:
2014 Bicycle Ride Calander