My chapter has this problem too. Many of the girls lose motivation as rush winds down. Its understandable because the weeks leading up to rush (we have recruitment about 3 weeks into the semester) we have lots of rush practices, which to some get either boring or stressful or both!
Our chapter tries to do fun stuff together during these weeks, like going out to dinner at a restaurant or the dining halls (wearing letters, of course!
). We also go to a lot of the beginning of the year school sponsored events like the comedians, hypnotists, fairs, etc.
I love the sunshine groups idea, thats really cute.