Check this out! It's the “Thumb Thing”...

Simply put the Thumb Thing on your thumb and pick up a book; the two wings will hold the pages open more easily than if you just used your hand, making reading more comfortable. Ideal for reading in bed, in the bath or at the beach. Since it allows you to read with one hand, it’s great for commuters, especially if they have to read standing up. When you are finished reading, place the Thumb Thing in the top of the book as a book mark.
And comes in all different sizes:
Small Thumb Thing should fit fingers with ring sizes of 3 to 6.5, Medium Thumb Thing - ring sizes 7 to 8.5, Large Thumb Thing - ring sizes 9 to 11.5 and Extra-Large Thumb Thing - ring sizes 12 and up.
I'm so excited...it's one of those things that I had no idea exsisted but I don't know how I could lived without it.