My home chapter also had the babysitting list--- it's a win-win scenario!
We also invite our area alum to come back for a special "Recruitment Week Preview"-- at UCF, we call it "Pi and Tea." It gives alum a chance to see the house, hear about the chapter, and for the collegians to practice conversation, etc. (some of the chapters that still do skits perform their skit; those with videos show their video). And of course, it's a great chance to have a meal together! In the spring, USC hosts an Alumnae Tea for the whole chapter and the alumnae, and they also hold their Jewel Degree that day. This year, UCLA hosted Founders Day in conjunction with JD.
One of the chapters and alum assoc just won a convention award for co-hosting a large charity golf tournament together for RMH. They do it every year

Isn't that a great idea for joint-project?
UCLA and USC chapters got together with the LA alum last fall to co-present ADPi a Lifetime Experience.
Does anyone else have any ideas? Challenges keeping you from developing relations?