Help, Any Creative Ideas To Keep People Dry??

This coming sat night, we are throwing a party in honor of me. Since my husband has never thrown me a party, we are making it a bash, my problem is in NJ it has been raining on and off, sunny one min and down pour next!!! i fear that my guest will bail if i don`t have a way to keep this a great party, even with a little drizzle? i have tried to find a tent for my back yard but they will only fit 3 tables, and are highly expensive,only enough seating for a few of our guests. I need a creative vision to ensure my first real birthday party is not a waste of time or money!!!! thanks brandy