Instant hand warmers are great - just shake 'em up, and you've got spontaneous warmth to thaw your hands during the cold winter months. But they're awfully expensive, and not because they're complicated to manufacture. In fact, you can make them yourself in a few very easy steps.

While we're all sitting around waiting for RFID tech to really take off at the consumer level, people here and there are dabbling in different ways to make use of that kind of technology. For instance, have you ever thought about making your own card scanner to unlock your office, or even bedroom, door?

Manufacturers of Android smartphones often won't provide an updated, custom version of the operating system for models they no longer sell, so users can't take advantage of new features. For older phones, there's a workaround: CyanogenMod, a free OS built from the source code for the latest versions of Android that Google releases to developers. CyanogenMod is very similar to the official Android platform, but it includes a few extra features, such as Wi-Fi tethering, a screenshot tool, and more security and power-management settings. Many users also say it runs faster than their phone's original Android software.

Light 18-volt batteries have become the standard for cordless power tools, but they often underperform when faced with difficult tasks such as boring large holes into wood or metal. To produce more strength without resorting to a heavier, higher-voltage battery, engineers at MilwaukeeToolsredesigned the motor of the new M18 Fuel drill. The result is a tool that generates about 25 per cent more torque than the average 18-volt drill and can create big holes faster than any of them.

If you've ever gotten bored riding an excercise bike, you might be interested in this. It's a virtual bike ride with one little trick: it's almost completely mechanical in nature.

Sure, you can buy fun things. But if you make them, you get the fun of construction plus the fun of use, with a dash of satisfaction and an anecdote to tell anyone who uses your creation. These three projects - a sledding winch to get you up a hill, a giant version of the board game Operation, and an Angry-Birds-playing robot - are all homemade.