No hot water on Saturday Morning

Home-owners face problems around the house and I am no exception, but no hot water on an unusually cold April Saturday morning is not a good surprise by any means. I am a big DIY fan for the small problems around the house. See my other posts on 5 DIY Things to do. However when it comes to appliances that run on gas, I am initially little hesitant to touch. But when things break on Saturday, you have no other option than take a first look and analyze the problem before trying to make a call which can cost you at least $100 for someone to show up on your door. I had very generic idea about how a gas water heater works, but absolutely no idea on how the appliance maintains a small flame for thermostat to kick and use the flame to heat the water.
After a basic google search I got the clue on where to look; it was pilot light assembly one of the very important part of water heater system. Pilot light keeps the flame burning which remains the gas valve open.
So how pilot keeps the flame burning? 
Actually Thermocouple does the real job. Thermocouple is an electronic device that senses if the pilot flame is hot enough to sustain burning the gas fuel from the burner. If the thermocouple thinks it's safe, then it keeps open the main gas valve located in the pilot assembly. If the thermocouple does not sense enough heat from the pilot flame (such as when the pilot is out), then the thermocouple shuts off the gas valve to the burners.
How did I know that thermocouple was bad?
I found a very nice video on how to isolate the thermocouple in the water heater. This guy has done an extra ordinary job of illustrating how to test if thermocouple is good or bad. Basically, you run a quick test of lighting the pilot by overriding the pilot button. In my case, I was able to conclude that my thermocouple was burned out as it was not holding the flame after depressing the override button for a min. Now, when I was done isolating the  problem with thermocouple it was just the matter of finding how to replace it. The keyword search on "Thermocouple replacement gave me plenty of good links using which I was able to get a Honeywell Thermocouple for $10 from Home Depot and replace it. After a short trip to Home Depot and few keystrokes later, we had hot water again on Sunday morning. DIY works with the help of great you tube videos, Thanks to the Pros who are willing to provide quality tips and tricks on you tube absolutely free !!