Oogoo and Raspberry Pi
While I haven't been doing much blogable myself, I have recently found a couple of interesting things via Hack A Day:
Oogoo is a moldable silicone clay that is easy to make from readily available substances. The main problem for what I'm thinking of using it for is it releases acid as it cures, so I'm not sure using it to encapsulate metal is a good idea. Still, it looks like something fun to work with.
Raspberry Pi while not shipping yet (they hope for November/December) looks very interesting -- a $35 (or $25 for the less well configured one) low-power credit-card sized Arm board running Linux with a reasonable amount of I/O (USB, Ethernet, HDMI, I2C, I2S, SPI, serial, audio, composite video, and GPIO). The alpha version is running Debian, but they plan on shipping with Ubuntu or another distro. While the first version is aimed at experimenters (no case, no power supply) they are a UK non-profit aiming at the education market. This is not a direct competitor with the OLPC, which is aimed at younger children.