The Lone Star State is the only state in the Union that has as part of it's constitution the right to ceceede into it's own Country when it wants to.
There is so much to do in Texas, it is hard to know where to start. I have family in the state, so I started with where they are. Dallas & Fort Worth has a strong ranching and stock history, though with the amount of Malls, you may not get to see that part easily. The Visitor and Convention Bureau lists the Malls, Hotels and Meeting spaces throuout the city. Fort Worth (worth every minute) has a wonderful combination of old archetecture and new businesses - and don't miss the cattle drive almost every day at the Stockyards!
The 'standard' places to go include the Fort Worth Zoo , The Dallas World Aquarium, and the Dallas Zoo. You may want to try out the Grapevine Vintage Railroad or the Meteorite Gallery in Fort Worth. If you want to go a little more Mideval, try Medival Times or the Scarborough Renaissance Festival. A little more home-grown history can be found at the Six Floor Museum at Dealey Plaza, a John F. Kennedy Memorial.
The Dallas-Fort Worht area is huge and contains multiple cities. Irving is in the north of the Metroplex. Addison, Carrolton, and Farmers Branch are clustered in the North East part of the area. Hurst, North Richland Hills and Bedford are in the North West area. Duncanville is in the South and Mesquite is in the East.
Grapevine is a large city in the Dallas-Fort Worth northern reaches, just north of the Dalls-Fort Worth International Airport. I have been to the Grapevine Mills shopping complex - huge is not enough of an adjective. Grapevine was also the first place I saw a Brazilian Steak House, like Boi Na Braza - Meat on a stick!
If you need to do Ultra Family Fun, try the Six Flags over Texas in Arlington. Hurricaine Harbor is a Six Flags park, too.
If you need to have help finding all those places, you can get a map from the Dallas-Fort Worth section of Map America. To get around in the Metroplex, try the Trinity Railway Express.
South of THe Dallas-Fort Worth MetroPlex is Huntsville, home of Sam Houston.
If you want an old-world flavor in the Texas Hill Country, try Fredericksburg(German heratage, Texan hospitality). They have things going on all year, and if you get their mailed pamphlets, you get a listing of some really cool things to do. Being just North of San Antonio And directly West of Austin, it would make a great part of a loop tour of central Texas.
As I was going over the information from Fredericksburg, I found one of the longest website names I have ever seen. www.lavender-trails-of-the-texas-hill-country.com. O.K., I have seen longer ones from the gonvernment, but I had to include it.