It depends if the shower if for a boy or a girl. Obviously if it is for a boy the light blue and green colors are popular. If it is a girl pink of course. Some different themes that are popular are bears, storks, strollers, ducks, anything with cute animals.
Some good themes for a Baby Boy baby shower could be easy with just blue or more creative with things like rubber Duckies,Monkeys,Prince crowns, and so on. http://www.partypail.com/boy-baby-shower-themes.html
http://www.babyshower101.com/baby_shower_themes.html explores and gives you plenty of ideas of baby shower themes that you are seeking for. Once you go through them all, you can also explore other aspects of that site as it very useful since it is specifically everything baby-shower-related.
There are many different baby shower themes. I think the most popular is probably the stork. Noah's ark is also a popular theme. There are monkey themes, bear themes, all different type of animals. They also usually have both in either pink, blue or yellow depending on the sex of the baby.
Examples of themes include Winter or Summer (depending when the baby is born or due!) garden-themed, eco-friendly or the good-old-fashioned boy or girl themed shower.
Following are some fun ideas for a baby shower: Stork delivery theme, nursery rhyme theme, a Velveteen Rabbit theme or The Very Hungry Caterpillar theme. Just be sure to have lots of color and fun foods.
I would think most games would be gender neutral at a baby shower... but you could decorate onsies with boy themes (trucks, airplanes, dinosaurs). Here is a website with some baby shower games! http://www.babyshower101.com/baby_shower_games.html
Some ideas for baby shower parties are animal themes, such as a jungle theme, or a Noah's Ark theme. You could also so turtles, elephants, monkeys, or giraffes.
Some baby shower theme ideas include animal themes. These can include: butterflies, ladybugs, safaries, monkey, etc. Noah's Ark is a cute idea as well.
Some ideas for a boy's baby shower would be themes such as cowboy, trains, circus, baseball, football or any other sport. You can buy decorations and paper goods that relate to the theme you choose.
Visit http://www.partypail.com/babyshowers.html for some great baby shower items. Better yet, these items are cute, come in over 60 themes, and are affordable for any party budget!
A fun theme for a baby boy shower could be John Deere tractors! You could have a tractor cake made, buy light and dark green plates and napkins, and register for some fun tractor/farming themed baby clothes and other items.
Any type of baby shower favors are good for a twin baby shower as well. Chocolates, little photo frames etc. You can find some ideas here: http://www.prettybabygifts.com/baby-shower-favors.html