D.B.
I got these little terra cotta "brown sugar keepers" from one of those fundraiser catalog sales from my daughter's school. Here are some like it:
http://www.fykitchen.com/Details.cfm?ProdID=616
You just soak them and put them in an airtight container with the brown sugar. The sugar around the terra cotta will get white and hard, but the rest of it stays fluffy and soft!
Good luck!