This seems like it should be a common question, but a little searching didn't reveal an answer, so I'll ask it anyways.
I picked up a Giant Farrago hybrid on CL for the Right Price (i.e. FREE). One of its problems was a destroyed cable housing coming out of the grip-shifter for the RD. I figured, no problem, I should be able to fix that. I measured 50cm and bought a length of housing (with plastic caps) for $2 from my LBS. That guy was probably laughing with his buddies as soon as I walked out the door, "Look at that noob, he's going to try to put old cable through new housing!"
A few hours and much frazzled cable later, I've given up; I'll be taking it into LBS for a new cable (shouldn't cost much I'd imagine), but for future reference, how is it possible to get cable into and out of the housing end-caps? It's hard enough to get all the strands INTO one end, but getting them all to come out the plastic cap on the other end, when you can't access the inside of the hole, seems impossible!
Is there some kind of mini wire nut that can make the end firm enough to get through the holes or something?