I've come across plenty of good websites with games however a few tried and tested ones I've used are:
Baby Socks Matching Game Baby Shower Game
In the center of the room, place a pile of (separated) 10-15 pairs of baby socks (solids, patterned, and different sizes). Each guest gets 10 seconds to match them. The guest with most pairs of matching socks wins a prize. (* the more patterned socks, the harder).
Baby Songs Baby Shower Game
Set a timer for 3 minutes. In that time have your guests, (individually or in teams) write down as many songs that have the word baby in the title. The person/team who has the most wins.
Bubble Gum Babies Baby Shower Game
Pass out a piece of pink, wrapped bubble gum to eat guest. After each guest has chewed their piece, set the timer for 1 minute and see who can form the best bubble gum baby with their gum.
Diaper Sniffing Baby Shower Game
You will need 10 or so diapers for this one. In each diaper put drops of different scents (vanilla extract, baby lotion, chocolate, root beer, etc). Give each guest a pen and paper and pass the little diapers around and have each guest sniff them and write down each scent. Whoever guesses the most correctly wins.
(Another variation on this one is using different melted chocolate in the nappy and they have to guess which what is - ie. Cherry Ripe, Old Gold etc.) Gross but it keep getting requested???
Baby Shower Game Pin the Pacifier on the Baby
Have up to six guests try to pin a pacifier on the mouth of a large picture of a baby.
(Just like pin the tail on the donkey)
Guess the number of lollies in a bottle. Hand each guest a small bit of paper and pen. Pass the lolly filled bottle around and each guest writes their guess on the paper. Collect the papers and the closest correct answer wins the bottle.
Hope this helps. I've doing my sister's shower in two weeks as well so you've reminded me to get cracking grin