I know, no big deal, and I thought so too. I have spare cables and I have changed them in the past, but that was back in the days of friction shifters. My two year old hybrid has indexed shifting and I found out I had no idea how to open and insert the cable in the grip shifter. My bicycle repair book is from the 70s.

I will never cease to be amazed at what you can find on the internet. Following a bit of searching I found this site, which has a wonderful video: http://bicycletutor.com/grip-shift-cable/

I never would have figured this out on my own, and sent him a $5 donation for his coffee fund. I have never changed a cable on my touring bike, which has STI shifters, and unfortunately he doesn't have a video for that.