Summertime often challenges parents to stretch their imaginations to keep children busy. ''Activities for Anyone, Anytime, Anywhere'' (Boston: Little, Brown, $13.95) by Jeri Robinson of the Boston Children's Museum offers a large repetoire of creative ideas to tap when the project list runs low. Here are a few ideas to try:
* Edible collage is an art and craft activity children can eat when they're finished. To make a collage, spread a spoonful of honey over the entire surface of a paper plate. Make a design on the plate using goodies such as miniature marshmallows, pretzel sticks, corn chips, small candies, popcorn, carrot curls or coins, raisins, nuts, flaked coconut, or chopped fruit. Admire the results - then eat!
* Body tracing: This activity requires large pieces of paper such as a roll of butcher paper, brown wrapping paper, or several large grocery bags opened up and taped together. One person lies down on the paper and someone else draws around him or her, making a life-size paper doll. Children can have fun decorating the doll to look like themselves or any character they choose.
* Impromtu dollhouse: This project requires glue, scissors, four shoeboxes, spools, toothpaste or bottle caps, scraps of fabric, odds and ends of giftwrap, large stamps, small pictures from magazines, and smaller boxes. To make the dollhouse, stack the shoeboxes in any arrangement, making sure they are open on the same side. Make furniture out of the items listed or other small objects found around the house.
* At the shore: Styrofoam egg cartons make good homes for collections of small objects found along the shore. Children can see how many kinds of shells, pebbles, smooth beach glass, and driftwood they can find.
Sand castings are a fun beach project. To make a sandcasting you need: sand, a bucket, water, plaster of paris, found objects such as shells or pebbles.
Prepare the sand mold for the cast by digging a shallow hole in the sand and smoothing it out. Decorate the mold with found objects or make imprints with a stick or your hand. Following the directions, mix the plaster in the bucket and pour it into the mold. Let it dry for 15 or 20 minutes before removing it from the sand. Brush off any loose sand and the plaster casting is finished.