Turn some old SLR bellows into a homemade macro lens for your digital single-lens reflex camera.

DIY dSLR Macro Lens [link]

Thanks to Bold Lentil for this submission:

« You’ll never look at a screw the same way again. Starting with an
anecdote from a bar in Brazil, this post has a simple DIY to make
your own bottle opener. From there it’s simple to consider how
to fill your world with built in bottle openers and a decent example
of extreme re-use. »

Simple and elegant. There’s no excuse to go thirsty!

World’s simplest bottle opener [link]

These marble picture fridge magnets thingys make great stocking suffers. Useful too, to stick on the fridge or on any metal surface, such as a file cabinet. They keep papers from flying everywhere or just be used to decorate your cube. The marbles you need for this project are very easy to find. Try home decoration shops (people put them in jars to decorate) or gaming stores (they are used as tokens in many board games). As for the magnets, you can use any small magnet, really, but the best would be to use rare earth neodymium magnets (not rare heart as Ive seen in a store). You can easily order them online if you don’t have any.

DIY Marble Magnets [link]