what would happen if/when...
 

you ran a pair of 8ohm house speakers off of a car stereo deck, say for tunes around the campfire?

I would say they would work...My astro contained two speakers in the back that were 12 ohms...Most car speakers are 4 ohms..So 8 ohms would work fine...

Hope this Helps:)

Yup, it will work fine. You will have one noticeable drawback. That will be that the overall volume level is far less than a 4 ohm speaker would be so do not expect it to get real loud by comparison.