For this game you will need 10 baby bottles and a small ball (a tennis ball works great.)
Set the bottles up at the end of the hallway in a triangle like bowling pins. Guests take turns trying to knock down as many “pins” as they can. The one who knocks down the most pins wins!
As a prize for this game, you might give a coupon for a free game of bowling, or as a gag, an old used pair of bowling shoes! Mom-to-be should get the bottles at the end of the shower.