I-40 and I-35 intersect here, you've got to come here.
Oklahoma is a nice place. Varied geography and diverse people. Plains to the west and hills and trees to the east (split right down the middle of the state). If you like outdoors, there's tons of scenic beauty. It's inexpensive here as well. As far as any other "must see" attractions, I think they've been discussed already. It's mostly an outdoors state with tons of lakes but there are maybe a few other places to see.
Unless you like Indian casinos. We've got lots of those.
1. NE Oklahoma - Some of the most beautiful scenery you'll ever set eyes on.
2. College football - we have 3 outstanding division I teams in the state. Fall in Oklahoma is an awesome time.
3. Lakes, lakes and more lakes. If you're into fishing, swimming, boating, or just about any outdoor, water-related activity, this is a great place to visit.
4. Diverse terrain - You can visit, mountains, plains, forests and deserts in a single trip.
5. Finally, the people. You'll not find a nicer group of people in the country.
If you visit Bartlesville you must go to Murphy's Steakhouse and order what they call a Hot Hamburger with Brown gravy. Nothing beats it. 2 pieces of Texas Toast. A big hamburger patty on top of that and a pile of fries on top of the burger and then all of that is smothered with Brown gravy. Dang. Im getting hungry just thinking about it.
I'm from western OK and not a whole lot going on there but there is a great park called Red Rock Canyon we went to as kids.. great hiking and beautiful. other than that I would stay east, Grand Lake is nice.