Science and Engineering: Links - Science Books - Blog Directory - Education Blog Directory - Science Fair Directory - Sites for students and teachers
Our favorite choice, the Awesome CatCam - let your cat take photos for you. Educational and just plain cool.
Lego Mindstorms are a great example of the fun learning opportunities available today. Having fun and learning is a great combination.

Cool product and nice gift: ezVision Video iWear the iPod Video and DVD Movie Goggles. Using these is like watching a 50 inch screen and you can easily carry them with you anywhere. You can use them to watch videos from your iPod.
Crystals and sculptures created by Bathsheba Grossman are great gifts for those interested in science and engineering. The art itself is very cool and the site includes interesting information on the science represented by the art and the engineering behind creating the art.
A non-gadget option is a service that lets you create your own custom book (I find the quality and prices amazing - 150 page full color photo book - 1 copy for $39.95, for example, with less expensive options available too).
Another option: AlienFly RC Mosquito Helicopter (fits in your palm - sale price under $30)