I found these containers for cereal and milk at The Container Store the other day and I love them. I have seen them at other stores, such as Staples or Office Depot, with the back to school supplies as well, but only bought them recently.
The bottom container has a contained gel that will keep things cold when it is frozen and the lid has a folding spoon that snaps in place. Normally I shy away from unitaskers, Alton Brown's term for things that do only one thing. With this, however, I like that everything is self-contained when it is fully assembled.
My kids love cereal and although it can be very healthy and economical, it is rarely convenient or practical to have away from home. Lately we have been leaving the house very early, too early for breakfast, so these containers fit the bill nicely. I see a world of possibilities for these containers beyond cereal and milk. I'm thinking yogurt and granola, berries and cream, crackers and dip, veggies and dip. Just the other day a girl was having crackers and lobster spread and this apparatus would have been perfect. If I had something like this when my children were babies, I might have used it for formula and infant cereal when we were out of the house.