YakTrax. "Chains" for your feet. Only $20.
Enabled me to be the 1 of 2 of 7 scheduled employees at work Monday (13" of snow in Portland, no one shovels their sidewalks), walk 6 blocks to buy a supplementary space heater Tuesday night, and get 4 22 0z bottles of premium high-alcohol beer today.
http://yaktrax.com/