It’s called the Kokuyo Mirikeshi Variable-Width Eraser, it can erase with five different edge widths (6mm, 5mm, 4mm, 3mm and a point) and I wish I had it when I was at school. [White Rabbit Express via Book of Joe]
It looks and acts like an ordinary eraser until you open it and discover it is also a USB memory stick (and part of a campaign for Alzheimer’s awareness). [Ads of the World via Likecool]