A few ideas that I have that havent been mentioned are:
1.) Paintball
2.) Laser tag
3.) Maize maze - which is a cornstalk field that has been developed into a maze for people to find their way through it. this is one located in lancaster, pa but if you you type maize maze into google their are lots of websites that pop-up and there are usually a couple other things to do there as well. to complete the total maze finding all the check points usually takes at least two hours you could divide up into groups of four or so and work your way through the maze.
http://www.cherrycrestfarm.com/cornmaze.asp
All of these of course depend on the amount of money and resources you have available to your chapter