Open Gym

Pump It Up! There are location in Olathe and Shawnee. Olathe is open Tues and Fri, and Shawnee is Mon and ??. I know they have a website. My kids are exhausted when we get home!
Have U tried the zoo? There is plenty to see and ample places to run, lots of walking, a jungle gym, children's barn, carosel...they do have a yearly pass avaliable. When the weather is nice we frequent them sometimes twice a week.
Depending on how adventorous U are there is also Worlds of Fun. They have a kiddie section that will keep them entertained for hours.
Good luck to U.

Matt Ross Community Center (80th and Metcalf) has a big play structure (like at a McDonalds, but clean) that is open to the public without a membership. If you get a membership (way cheaper than any other gym I've seen) you can just take them to the gymnasium (nobody's in there during the day most days) and let them run, chase balls, shoot at the basketball hoop, etc.)
There is a sister community center at approx. 119th. I don't know what their facility is like, but I'm sure you could find out online.

Dave's Gym has open gym time on Friday mornings! It's a lot of fun!

I haven't been yet, but my friends told me about the Sylvestor Powell Community Center. The hours are 9:30-11:30 tues-thurs each week. $2 for first child, $1 for additional kids. My friends have taken their kids there and said they have a lot of room for kids to play indoors and run around. Here is the contact information:
6200 Martway
Mission, KS 66202
Tel: ###-###-####

I know that Millennium Gymnastics has a great open gym. They are located across from Central Library in Lenexa. Not sure of their exact times, but the number is ###-###-####

Kansas City Gymnastic and Cheer have an open gym as well, they are in Olathe near the new Bass Pro. Monkey Bizness in the Great Mall of the Plains is also a great place, it has just opened but several people I know have been there and said it was a blast.

Hi A., I take my kids to Cedar Ridge Church. It is also known as the coffee shop. It a great place for the kids to run and get rid of their extra energy! You can fine them at http://www.parksidecoffeehouse.com/psch/. Whenever the coffeeshop is open so is their open gym and it is free! Except for the coffee/snacks. You may also go to lenexa community center on mondays and wednesdays from 9am-11am for $1 each child and then can run and play as well. Hope this helps!