Here are some games we have played at showers I have attended: Baby Shower Bingo (leave a few squares blank for guests to fill in prior to gifts being opened), Don't Say Baby (You can use diaper pins, safety pins, clothes pins, or make necklaces w/ baby themed trinkets and anyone caught saying baby after the game begins has to give up all the pins/necklaces that they have to the first person that calls them on it. The person with the most pin/necklaces in their possession at the end wins), How Well Do You Know (ask the parents to be some questions before the shower like names they have picked out for boys and girls, due date, their full names and birth dates, misc. other questions like color of nursery etc. Then ask the guests to see who gets the most right), Baby Words Scramble (they have to unscramble baby words), Guess Mommy To Be's Tummy Size (each guest has to pull off toilet paper in the length they think would be closest to the measurement around the mom to be's tummy without actually measuring or wrapping it around her), Guess The Baby Food (take a few baby foods and mark with numbers and remove the label but be sure you have multiples of the same colors, no duplicates, and you need to keep a master list. then pass the UNOPENED jars around for people to guess which fruit/vegetable is in the jar...carrots, peaches, squash, peas, green beans, spinach, bananas, apples/applesauce, pears, is what works while throwing people off....then since they are unopened they can go home with the guest of honor).
For my sister, we hung a clothes line and asked that guests bring an item (not all in newborn sizes) of clothes to hang on the line (served as gifts and decorations) and then we used clothes baskets as centerpieces and various people filled them (me, my other sister, and this sister's friends were throwing the shower so we each took a basket or two to fill with laundry products, laundry items, etc...themed baskets if you will.
This shower was right around Halloween/Thanksgiving so we did some Harvest themed door prizes (candy jars etc) so they were unisex.