Here are some tips for creating a fuzzy illuminated scarf with color-changing LEDs, with a relatively simple process that is suitable for someone with limited sewing or soldering experience.
The lens of each of these RGB LEDs contains its own red, green, and blue emitters, and a built-in processor to make it blink or fade between colors, so you can achieve a fairly sophisticated effect with a simple circuit, and no external driver. The flexible connecting wires are concealed by a fabric lining, so the finished product is very comfortable and easy to wear. The lights create a nice diffused glow in the fur - wear it as a conversation piece, fashion statement, or safety accessory.
The number of lights in the design can be scaled up or down, with no need for a current-limiting resistor, although battery life will decrease as you increase the number of lights (unless you upgrade to a larger 4.5V supply).
Step 1: List of materials
piece of faux fur for scarf (60" x 9" for the example shown)
fabric for lining (60"x9", or can be more of the same fur)
extra fabric for battery pocket
strip of velcro, approx 3" long
razor blade (to cut fur, optional)
sewing machine (optional)
buttons (standard 2-hole sewing type, approx 1/2" diameter - not rubber, not metal. most plastic buttons are reasonably heat resistant. available at craft stores, or by the pound at buttons4u.com)
Electronic materials and tools:
color-changing RGB LEDs (the type with a built-in flashing or fading circuit, with two external leads - a fast blinking version is available at allelectronics.com, slower fading versions are available on eBay)
battery holder for 3 AA cells, batteries
on/off switch (optional) SPST pushbutton (non-momentary)
insulated connector wire (stranded wire in the range of 20-24 GA - can be obtained by separating pieces from standard ribbon cable)
helping hand stand with spring-loaded clips
Other stuff you'll need:
soft surface for pressing LEDs into buttons while bending leads (electrostatic work mat or yoga mat)
hot glue gun and glue sticks
pen or marker