General parts:
--20mm coin cell (Sparkfun[currently out of stock], Radioshack)
--20mm coin cell holder (Sparkfun, Radioshack)
--3mm LED (Sparkfun, Radioshack)
--Button (Sparkfun)
--Copper tape (Sparkfun, Amazon) or conductive ink (Bare Conductive)
Tools:
--Card stock paper or thin cardboard (I am using card stock throughout this instructable)
--Pencil
--Hobby knife or scissors
--Breadboard
--Jumper wires
--Soldering iron
--Solder
--Helping hands
--Multimeter (optional, for debugging)
Sensors (there are many possibilities):
--Photocell (Sparkfun, Radioshack)
--Thermistor (Sparkfun)
--Flex sensor (Sparkfun)
--Trimpot (Sparkfun)
--SoftPot (Sparkfun)
(The description of each sensor is in the next step, or check sparkfun for a better one.)
We've all forgotten to take those sticky name tags off our shirts before tossing them in the wash, and the resulting residue is incredibly difficult to remove. The next time this happens to you, just reach for your nearest bottle of nail polish remover.All you have to do is set the shirt on a towel, and spot test a drop of acetone-based nail polish remover in an inconspicuous place. It shouldn't harm most clothes, but better safe than sorry. Assuming it didn't damage the shirt, spread some more around the glue residue, and rub vigorously with a hand towel to loosen it up.This trick works best for natural fibers, but tossing a synthetic fiber shirt in the freezer can actually accomplish the same thing. For more advice on cleaning glue residue off of synthetic fibers, be sure to click through the source link.Yes, It's Possible. Remove Name-Tag Residue From a Shirt | Real SimplePhoto by Joe Belanger (Shutterstock).
OS X: Odds are, your Mac's Dashboard has fallen by the wayside in recent years (even though it can be really useful), but widgets can still be really handy for certain tasks. WidgetRunner frees them from their prison in the Dashboard, and lets you run them alongside your desktop apps.There's an old trick to do this with a terminal command, but it doesn't seem to work for most Mountain Lion users. WidgetRunner works on modern Macs, doesn't require a terminal command, and doesn't even saddle you with a complicated interface to set everything up. Just open the app, click the main dropdown menu in your menubar, and hit "New Widget." Your custom-installed widgets can be found in /Users/username/Library/Widgets, and the default widgets will be in /Library/Widgets. Just click the ones you want, and they'll populate on your desktop where you can drag them wherever you wish.By default, widgets will act like regular windows, and disappear behind any other active applications. But if you want one to float on the top of the screen, just right click it and change the widget position to "Top." You can also set widgets to "Desktop" mode, which effectively turns them into part of your wallpaper. You won't be able to interact with it at all unless you first click the WidgetRunner icon in your dock, but it's great for passive information widgets like weather or stocks. The relevance of most widgets has been diminished by more powerful web apps over the years, but if there are any that hold a special place in your heart, this is a great solution to keep them close at hand.WidgetRunner (Free) | MIT via MakeUseOf
Paper craft is a lot of fun, I particularly like the models that move. I wanted to try my hand at making my own movable model. When I came up with the idea of making Harry Potter with a moving arm it occurred to me that it could be even better if I incorporated an LED into the wand. So as he raises his arm to cast a spell the tip of his wand lights up. 
Paper model:
So you want to make a robot? Don't know where to start? How about you learn how to make a robot with me and make James!
For this build we will be using the Arduino Uno with a Prototyping Shield. You could use whichever Arduino you want with its own Prototyping Shield or Breadboard. 
In this instructable, I'll show you how to make a simple rope dog toy using two Matthew Walker knots. Many rope toys you can get at the pet store consist of a rope with two overhand knots in it. The Matthew Walker knot is much more symmetrical and less likely to come untied. With three strand rope, the Matthew Walker knot makes a great stopper knot which prevents the rope from unraveling. I'll be using this knot in other dog toy instructables, so follow me to see more!
I always use cotton rope for my dog toys. It's all natural and isn't a big deal if your dog swallows pieces of it. I get my rope from both Knot and Rope Supply and Amazon. Knot and Rope Supply sells cotton rope by the foot in a number of different sizes: http://knotandrope.com/store/pc/viewCategories.asp?idCategory=6