Houston Dock Dogs is having an event on 5/16-17 if you want to check it out. It is in Plantersville, TX (about 55 miles NW of Houston) at the Jest Fur Fun Training Center.
There is also a playday tentatively set for 6/20. It should have dock jumping practice for sure and possibly lure coursing, agility and conformation run throughs. Dock jumping is $20/dog for unlimited jumps and everything else should be $5 a run.