Here's two neat products from Craziest Gadgets, one for people with a firm grip, and one for people without:

The Sundesa Blenderbottle is a no-electricity way to blend things (like a protein shake at the gym, for instance): Just drop the blenderball into your mix, shake the BPA-free plastic container up and your shake's ready.

Black & Decker's Lids Off Jar Opener is for those with arthritis. Pop a jar in, press down on the oversized dome button on top, and the jar's open without the strain.
Both products are currently drawing rave reviews on Amazon (Blenderbottle here, Jar Opener here).
Comments
thanks for the coverage.. interesting contrast between the two devices- didn't think of it that way when i posted them separately
First principles people... why do we insist on designing a gadget to mask the inadequacies of another product. Am I the only one who gets frustrated by this? The lazy packaging designers working on these jars need to be slapped in the side of the head with a wet, stored and sealed for your convenience, soggy North Sea herring. End of rant.. continue.