A.G.
i have two ideas....
how about a bunch of bananas?
or...
how about a palm tree with three small monkeys hanging from it...trunk can be light yellow, top green. this kind of goes along with the 'Three Little Monkeys Sitting in a Tree' preschool song. You can also put the centerpiece on a blue sheet of construction paper with an alligator swimming below. Again, it goes along with the 'Three Little Monkeys Sitting in a Tree' preschool song.
I hope this helps.