The Galileoscope is a special low-cost refracting telescope kit that is being distributed as part of the International Year of Astronomy (IYA). Galileo used a simple refracting telescope 400 years ago to observe the craters of the Moon, as well as the phases of Venus and the moons of Jupiter. IYA 2009 recognizes this important 400 year anniversary.
The Galileoscope is not a replica of Galileo's telescope, but rather an easy-to-assemble kit consisting of a 50 mm glass achromatic cemented doublet objective (way better than Galileo's objective lens) and a couple of eye pieces with plastic optics that can be used in three ways. It also includes the tubes and other parts required for assembly (no tools are needed). The basic eyepiece is a Plössl type and provides 25x magnification. There's an auxiliary eyepiece with a negative lens similar to what Galileo used. Its field of view is so small that it's like looking through a soda straw, so the main use of this is to show how bad Galileo had it when he made his early discoveries (though his view was even worse than this). But this eyepiece can be combined with the basic eyepiece and the included Barlow extender tube to provide a 50x eyepiece that works pretty well - good enough to clearly see the rings of Saturn, they say.
I just got a Galileoscope today, assembled it, and tried it out on some nearby trees and buildings. It works quite well, providing clear and sharp views, though the friction-based focusing is hard to set precisely. I haven't tried it on the night sky yet - maybe tonight.
The Galileoscope has been available online for $15 plus shipping, but the price is going up to $20 effective August 10 (their production and shipping costs were higher than expected). This is still a good deal for a telescope of this quality. The instructions (2 pages) that come with it are quite minimal and even a bit confusing, so I recommend that you download the expanded instruction PDF (7 pages with color photos) from the web site. There's also a nice 20 page PDF Galileoscope Observing Guide available for download.
Assembly is easy, but you should look carefully at the shapes and orientations of the plastic eyepiece lenses. There are several different types, and they have to be assembled in a certain order and orientation. They look very similar even though they have different curvatures and thicknesses. One tip: the negative lenses (thinner in the middle) will make distant objects look smaller and right-side up when you hold them a few inches from your eye. The positive lenses (thicker in the middle) will show an inverted image when held up that way. Look carefully to determine the flat vs. curved (convex or concave) sides of the lenses.
If you assemble an eyepiece wrong, things won't look quite right, but don't panic - you can easily take it apart and try again. No screws or glue are used in assembly. Just handle the lenses carefully by their edges to avoid fingerprints.