marcimatz shows us the Virtual Robot Experimentation Platform simulating the Expliner robot. Expliner (which is commercially available from Hibot Corporation is able to inspect very high power lines while power is on, and also manages to overcome spacers and other obstacles on its way. The Expliner CAD model is courtesy of Hibot Corporation. You can watch the robot in action here.
Vasilios Stergiopoulos made a LAN tester circuit that can save you when it comes to network cabling. The circuit is simple and can be made with 2 different ways, either using some IC's or an AVR, it can check the type of LAN cables (straight or cross) as well as possible faults. For long cables there is also a remote unit to ease things. Details and schematics can be found here.
For under $40, this is a soldering station with temperature feedback from the soldering iron tip. Unlike other cheap soldering stations, this one will control the power delivered to the sodlering iron, according to the set-temperature (from a potentiometer) and according to the feedback from the thermocouple pair on the soldering tip. Both set value and tip temperature are displayed on a 16x2 LCD