I do baby shower for a living, and have had two myself! This punch is the one thing that never changes no matter whose baby shower I am planning, it is SO good and I guarantee you the Mom-To-Be will LOVE it!
When shopping for the punch, be sure to buy plenty of supplies, this punch goes fast! So, for a small baby shower, i would suggest two liters of Ginger Ale, two cans of pineapple juice and one carton of sherbet. As for the sherbet, I ALWAYS get lime, it tastes the very best, but for a girl baby shower raspberry would make for a pink punch if you would prefer, and still tastes yummy! Now, for a larger baby shower, please stock up, the ingredients aren't too expensive and even if you have leftovers they can be used.
Keep either the Ginger Ale or the pineapple juice refrigerated, but not both. The day of the shower, while setting up, you can go ahead and put a half carton of the sherbet in the pinch bowl and add the COLD beverage, whichever one you refrigerated. When the guests start to arrive, it is time to add the room temperature beverage. This way, the sherbet melts a little, but not too much.
Now have the Mom-To-Be taste the punch because it is her day! Add more pineapple juice or Ginger Ale to taste, everyone is different, but I like more pineapple juice in mine. Enjoy! :)