In precalculus we finished our unit on logarithms by seeing what/why/how log graph paper is used. I showed them the crazy-uneven-looking paper and we got to it with:
Things that came up: name of our galaxy, how to do the work for the 2nd blank, giggling about Uranus, caution and care of units when you just see "58", number of feet in a mile, how much is a billion, how many millions in a billion, ...
I also love the type of examples that we used. Their homework that night was to find a sort of "show and tell" example about anything to do with astronomy. They came back with some cool facts, and we had fun sharing and being amazed at it all.