Our basement stays a bit too warm for winter vegetable storage, so this year we've decided to try something new - an instant root cellar.
This method is somewhere between an old fashioned 'clamp' (a big ole pile of vegetables covered with straw and a thin layer of soil) and a tiny root cellar.
We dug some holes and dropped in plastic bins full of root vegetables. The plastic bins make the storage a bit more resistant to rodents than a regular clamp, and burying the bin uses the soil as an additional temperature buffer.
After we buried the bins, we covered them with a few inches of straw for insulation and topped the whole thing off with some old seed bags to shed water (and keep the straw from getting soggy and matted down). We'll dig them out in a few months and see how it works!
There are lots of other ideas for outdoor storage in this article from Mother Earth News - we pretty much did their "Garbage Can Cellar" plan.