The Mini Sky Umbrella from Vat19 offers a nifty "auto-open auto-close feature that is great for those of us who are constantly toting too much around to devote two hands to our umbrella." Product page. Video after the break.
The 38-inch span of the Mini Sky Umbrella is plenty to cover two people. When collapsed, the mini design is only about 11 inches long, so it can fit easily into a purse or small work bag.[via Vat19]