MIT professor Neil Gershenfeld talks about his Fab Lab -- a low-cost lab that lets people build things they need using digital and analog tools. It's a simple idea with powerful results:
a small device which plugs into a $20 prepaid mobile phone to make a GPS tracker. The Tracker responds to text message commands, detects motion, and sends you its exact position, ready for Google Maps or your mapping software
Weekend Project Podcast: Make simple radios to listen too. These were made with materials that they could get their hands on and were small enough to carry around in a big pocket.
If your own water is safe from heavy metals, but you still like the way water tastes when it's been through something like a Britta filter, there's an easy way to convert the filter to be reusable, saving a ton of waste and a bit of money.
2.4GHz parabolic mesh dishes from Chinese cookware scoops & a USB WiFi adaptor! Called "WIFRY","WOKFI" or "WOKTENNA" (12"= 300mm diam) shows 12-15dB gain (enough for a LOS range extension to 3-5km)
allows you to control your computer with a simple remote, like the one you already use for your TV-set. It's very useful when you want to control a DVD or an mp3 player without having to stay at the keyboard.
A remote control car that can be driven over the internet or with a laptop wirelessly from up to 500m away. It has a live-feed network camera so that it can be driven without line of sight and a horn so that you can honk at people.
Made use of this info since my PSU did not support PCI-e, still have some strange behaviors that I blame on this mod but it has been working so I really don't care...
Always an interesting question... Ask any Firefighter what's in the pockets of their gear, and why. Everyone has different ideas, and there is typically an interesting explanation.