Jim,
I did one of those real estate auctions - what a riot ! You need to be Paul Shaffer and be ready for anything that can enhance the mood of the bidding. Basically, you need a little snippet after each property is won, because you can't play during the bidding.
Stuff like:
"We're in the money"
"Our house"
"Moving out" ......
anything that's cute, catchy, and recognizable. I did mine in a field, so all I had was a guitar, but it was a ball nonetheless.
Enjoy it ...... it's a change of pace from the routine !