I eat this everyday. I keep bags of frozen blueberries on hand.

1/2 cup of frozen blueberries (do not thaw)
1 packet of Splenda
Pour just enough soy milk, or skim milk, or fat free half-n-half to cover the berries.

Viola! The liquid freezes almost instantly around the blueberries and makes a nice sorbet type slush. Yummy, cheap, easy, and very good for your brain!

Sometimes I mix in frozen strawberries and raspberries, and they will require another packet or two of Splenda as they tend to be fairly tart.