Add raspberry sherbet to punch bowl. You can scoop it out or add the whole block if you're short on time.
Slowly pour ginger ale over top about 5 minutes before serving.
Add optional juice and/or fresh raspberries for garnish.
Video
Notes
It's best to add sherbet scoops so that the punch is easier to serve but the block of sherbet will eventually soften enough to be broken apart with the ladle.