Personally, my friends and family agree, fewer games the better. Most are hokey (or, as stated, done before). People just want to come, eat, chat, "oh-and-ah" over gifts, congratulate you , and go home. So, if I have to have games, I usually strive to make them funny, fast, and few.
Baby items in paper bags stapled shut - like cotton balls, q-tips, travel pad of wipes, etc. People pick-up and handle for a few seconds and try to guess what the items are. Person who guesses most wins.
Guess the baby food - buy several small jars of baby food, removing label and taping to bottom of jar. Person who guesses most correctly wins a prize. (Try figuring out squash from peaches!) I have even had a taste testing - using ice cream shop sample spoons. (Funniest but best if very small shower.) People love this one!
Plastic babies in ice cubes - first to melt in beverage wins.
Curling ribbon in a plastic container (1 parents can use for baby item storage later)- guess length of ribbon. Q-tips in container - guess number. You get the idea.
Instead of or in addition to games, try something like following:
Fold all napkins in shape of diaper putting dab of peanut butter or guacamole in middle of one. Person who gets dirty diaper wins a prize. (This is cheaper and easier than doing diaper pin for each guest.)
Trick guest by marking all but 1 of seats (plates, placecards or napkins) with an X on underside. Ladies, in particular, always look for a marked item at there seat to see if they won a centerpiece or some such gift. I like to to trick them by making them all think they won only to announce that one person has nothing marked at his/her seat and so is the winner. Gets them every time!
Congratulations and have a wonderful time!