Oatmeal enthusiasts have likely noticed that brown sugar wants to stick to itself and over time forms increasingly large, hard clumps. I suppose if left unchecked an entire container of brown sugar could become a giant-rocklike mass that one would have to chip away at with a spoon prior to each use.
A brown sugar softener is a terra-cotta puck (or bear, or other shape) designed to be soaked in water before beginning its new life right in your brown sugar container. I got one of these for my mom for Mother's day and it has really worked! I suppose I shouldn't find that as surprising as I do, these have been around for years and I'm sure many people were hip to this before me, but I was skeptical. I think the cutesy embossed designs made the brown sugar softener seem like a kitchen gadget for someone interested in inspirational magnets or cookie jars shaped like a chicken, not serious oatmeal consumers like myself.
I got mine for 2.99$ at Canadian Tire and soaked it for 10 minutes for 3 or 4 months of easy-scoopin' goodness. You'll know when you need to re-soak, as your brown sugar will start getting clumpy. A strange side effect is that some of the brown sugar has begun losing its colour and turning into regular white sugar around the edges, but it tastes the same as usual.
Image from Kitchen Stuff Plus