A party thrown by a dad-to-be's best friends to celebrate his pending fatherhood. This is potentially done separately, though in conjunction with one of the ladies' baby showers. Dachelor parties are a more responsible version of a typical male bachelor party, and include good bourbons, cocktails, cigars, and steaks, and other items (host's choice).
Guys, you are invited to Joe's dachelor party next Saturday, starting at my house. As he ladies celebrate Jane, we will strike off for the city and return after we've appropriately sampled some rare bourbons and eaten plenty of steak.