Extending an existing speaker wire

Audioquest makes a banana adapter for spades that I've used and was happy with just make sure the nut is on tight. BTW I think there is copper or silver.

You may try to buy two of these http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-285
and from them go to the "spare" speakers with two runs of speaker wire. You may terminate them at the other speaker end any way you want, or hook them bare.
When you feel like using the "spare" speakers, disconnect from the Klipschorns and connect to the "free" boards. That will do without changing the original speaker cables running to the Klipschhorns at all.

This is not recommended. You obviously need a longer set of speaker cables or move your second set of speakers closer together.

Thanks for the input guy's. I did find a banana plug coupling. For informational purposes they came from Radio Shack and the part number is 278-2098. I realize that this is not the ideal situation but is just for temporary non critical listening. By the way, isn't this just adding one more connection in the line since there are already two? Will one more really make that much of a difference?