Banana Bike Bag
Product Review (submitted on July 19, 2012):
I have this on my commuter bike so I can haul my keys, wallet, pager, and lunch (plus a spare tube, tire levers, and multitool) to work without messing around with a backpack. Paperwork & magazines will fit into it with one fold. Big enough to haul most things you'd wanna take with you, but not too bulky.