This game also needs prior preperation.
With the invitations, ask each guest to bring a baby picture of herself (or himself if it is co-ed) and using a document protector from an office supply aisle, tape pictures to a large blank poster as they arrive,being sure to number each picture. After everyone has a chance to arrive with their pictures, put the poster where all can see it, and have little memo sheets of paper, instruct every one to match the correct baby to the guest. The person who gets the most correct wins.
If many of the guests do not know each person's name, you might want to provide name tags to everyone; even to those who do not bring photos. I becomes even more fun as people are matched with non-participants.
Also, if no baby picture is available, a very young picture would suffice. Being in the info age as we are, some may want to scan and e-mail or fax their photos ahead of time.