I like to fix old video games, especially Atari games. Many of these older games do not amplify the audio on board and require a external amplifier. This makes fully testing a board difficult on my JAMMA test bench. I have adaptors that I make for all the normal signals, but didn't have an external amp. One day someone pointed out "why don't you just hook each adaptor up to a amplified set of PC speakers" Wow... why didn't I think of that. So I ordered a set of speaker "Y" cables so I cut cut off the ends and wire them to the board. Unfortunately the wires are so thin they almost instantly break off after you move the boards at all.
I ordered some 3.5mm headphone speaker jacks from Jameco (part #2095437, about $1.50 each) These are really nice because they naturally fit into the holes for the jamma fingerboard adaptor that I use from jammaboard.com to make my adaptors. (it does require a little figiting as they don't fit 100% naturally, but with just a little pressure out on the terminals they'll go in).
This works extremely nice as it fits good, has a solid connection and especially on Atari boards that only use 22 pins there is some extra space at the end of the Atari side for them to fit in existing holes that are not used.