I was going to suggest a weekend away when I saw the title of this thread. DH and I just sent my parents to Lilianfels in the Blue Mountains. It cost us a bomb ($1200 for one night) but they said it was the most amazing place they had ever been in their lives (and they frequently travel overseas).

So if you can muster up the gang to pitch in for a nice weekend away I'm sure they would love it. When we bought ours it came in the form of a "package voucher". That way they could use it when they were available to go. It was all inclusive (accommodation, dinner, breakfast, a lunch picnic and massages).