Jason over @ Hackszine writes:

Have you ever needed a D battery in a pinch, but could only find Cs? Since AAA, AA, C, and D batteries are all 1.5 volt cells, they are electronically interchangeable. They differ only in physical size and energy storage capacity. So, if you're in a pinch, you can cobble together an adapter with a few quarters or other suitable conductive material.

Even a 9-volt battery is made up of 6 1.5 volt cells, which are a bit smaller than a AAA (they are actually called AAAAs!). This could come in handy if all you can find is a 9 volt and you really need a AAA for your TV remote... You'll just have to spend some time cracking open the 9 volt case with a pair of pliers to get at the little cells inside.

Quick hack: The $1 C-to-D adapter -Link
9 volt to AAA conversion - Link

Kill your iPod (part II).

When it comes to audiophiles all is but lost.

With the advent of MP3, the idea of lossless audio seemed to have fallen upon deaf ears. Enter: FLAC, the Free Lossless Audio Codec, it compresses waveforms by finding similarities (like bzip), not by changing the the waveform itself (mp3 et. al.).

When it comes to playing FLAC on a portable, a HD based one is the only way to go because of the increased size of FLAC files -- roughly 1/2 the size of the original uncompressed stream. FLAC players are listed on the FLAC website, but as far as I see it there are only two choices for gapless MP3 and FLAC playback:

• Rio Karma -- purchase from Karma Limbo, his are pre-hacked with upgrades
• a Rockbox enabled device such as iRiver, or iPod

Scientists at the Massachusetts Institute of Technology think they're on the verge of making traditional batteries obsolete.

The researchers are working on a new device that uses carbon nanotubes to store and release electrical energy in a system that could carry as much power as today's lead or lithium batteries.

Check out the full article here