DUH!!!
You are from Houston, and not thinking about ...
LAKE HOUSTON!!!
We haunt lake houston almost every weekend. Great boating, very little crowds except on the busiest of holiday weekends.
Free launching at Deussen park on the south end. Pay launch at Huffman, and I think Kingwood. Might be a free launch on the river on the north end where 59 crosses the river. Used to be, not sure if it is there anymore. (edit 5/9/10--there is no launch on the river at 59. Went there to fish this weekend and it is all blocked to traffic)
Skiing and wakeboarding is best in the cove just south of the railroad bridge and just north of the dam, on those days when there is a south or south-east wind, which is most of the time for us. Also good skiing just north along the 1960 bridge and the bridge blocks the south wind.
Now if you want to camp, you will have to go to Livingston, which has some parks on the lake, but the stumps and weeds are horrible.
Somerville has some really good camping, especially near the dam at Somerville marina. You can pull the boat right up onto the shore and camp out like this.