Dear Need Help,
    This is a difficult question to answer not knowing more details about your meetings and what themes you have already done. Are you looking for activities for the children or for the adults? Below is a list of some of the more popular themes you could use and maybe it will spark an idea or two. This site has many ideas listed to go with these themes. So, once you pick one feel free to write back if you need help with ideas. I know there are a lot more themes then I have listed here. But this is a great start.
Good Luck,
The Preschool Teacher

List of themes:

Alphabet
Animals
Ants
Apples
Aquarium
Baby Animals
Balls
Balloons
Beach
Berries
Birds
Blues Clues
Body Parts
Breads
Bubbles
Bugs
Butterflies
Camping
Car Safety
Castles/ Medieval
Cats
Cherries
Children Around the World
Chocolate
Christmas
Circus
Clifford
Clothes
Clouds
Colors
Community Helpers
Count with Me
Day & Night
Dental Health
Desert
Dessert
Dinosaurs
Dirt / Mud
Disasters
Disney
Dogs
Doctor
Dolphins
Donuts
Dr. Seuss
Earth Day
Easter
Emotions / Feelings
Fall
Farm Animals
Father's Day
Fire Safety
Fish
Fishing
Five Senses
Flowers
Forest
Forest Animals
Fourth of July
Friends
Frogs
Fruit
Gardening
Graduation
Grandparent's day
Groundhog Day
Halloween
Hanukkah
Hats
Health
Hospital
Ice Cream
Jungle
Kites
Letters
Love
Manners
Maps
March Like a Lion & Lamb
Marsupials
May Day
Me
Memorial Day
Mice
Mittens / Gloves
Money
Monsters
Mother's Day
Music
My Family
Native Americans
Nature
New Years
Nursery Rhymes
Nutrition
Occupations
Ocean
Olympics
Opposites
Pets
Picnic
Pirates
Pizza
Plants
Pond Life
Popcorn
Presidents Day
Pumpkin
Puppets
Rain
Rainbow
Rainforest
Recycle
Reptiles
Rocks
Safari
Sandcastles
Seashells
Seasons
Seeds
Sesame Street
Shapes
Snakes
Snow
Space
Spiders
Sports
Spring
States
Strawberries
Sun & Moon
Summer
Teddy Bears
Thanksgiving
Time
Tools
Trains
Transportation
Trees
Tropical
Turkeys
USA
Vacation
Valentines Day
Vegetables
Water
Watermelon
Weather
Western
Winter
Winter Animals
Worms
Zoo Animals