For years I've dreamed about if New York had a pneumatic tube system working. Forget about transmitting data/documents -- use it to replace small deliveries!

For Chinese takeout or some tacos, for a book delivered from Barnes & Noble, for some lemons from the supermarket when you realize you've run out, for a bottle of shampoo from the corner pharmacy. Heck, try on different sizes of shirts and sneakers and jeans from different stores, and pack them back in the tube when they don't fit. Use it for mail too. Individual tubes that run straight into each apartment.

The convenience would be incredible. And now that we have software to intelligently and automatically route all the canisters, I often wonder why you never see it proposed more often.