I got my parents an Oxo Good Grips Jar Opener for Christmas, and it's surprising how delighted my mom in particular has been about it. Who knew you could win big with a $12 gift?
She has trouble with her hands, so the jar opener gives her a lot of extra leverage, making it easy to pry open everything from jars of baby food to large bottles of spaghetti sauce. Even if you don't have arthritis or RSI or any hand/wrist issues, the gadget makes opening jars a lot easier--no more thumping on the bottom of the jar with your palm or striking the lid against the counter to loosen it.
My mom actually already had a battery-powered jar opener, but she's not the most tech-oriented person and always had trouble getting it to work. Plus the batteries tended to die while it was sitting unused and taking up a lot of space in the drawer.
The Oxo Good Grips model isn't exactly tiny, but it's a lot more compact (flatter), making it easy to slide into a drawer with your other utensils. But it's big enough that you can find it amongst the clutter.
I've got an Oxo Steel Can Opener myself, and over all I'm impressed with the sturdiness and ergonomics of the company's kitchen tools.
$12 for the jar opener at Amazon: