Games
There are many board games designed for preschoolers. If you need an active game why not start a game of Mother-May-I? or you can hide toys around the house and send your child on a treasure hunt.
Newspaper golf is another way to spend a rainy day. Simply roll several pages of newspaper and tape them into a makeshift golf club. Cut out paper circles and place them around the house as holes. Then, let your child roll a ball around the homemade course. If you don't have a ball, you can wad up more newspaper and secure it with tape.
Crafts
Young children love to create things with their hands. Bring their imagination to life with "spoon people." This craft is simple. All you need is a few pieces of yarn to paste on for hair and a marker to draw a face. You can dress the spoon person with a cloth or an old sock around the spoon handle.
Cutting circles out of construction paper can become paper teddy bears. Designs are available online if needed.
Two pieces of colored paper can be used to make a butterfly. Place a clothespin in the middle of the two pieces to form the wings and let your child glue on pipe cleaners for antennae.
Pretend
Take the boredom out of a rainy day by putting on a play. Let the kids act out their favorite characters from their favorite TV shows or children's books. Children love to dress up so why not have them put on a silly parade? Wooden spoons and pans make good parade drums and drumsticks.
Picnics don't have to be in the park. Spread out a blanket on the living room floor and pack a picnic lunch.
If you have a child-sized tent, set it up in their room and let them camp out. Or you can drape a bed sheet over a table; pin one corner up to create a tent flap to crawl under the table tent.
Educational
Preschoolers learn through playtime. Print out pictures of ladybugs and write letters on their backs. Place these "bugs" on items around the house that correspond with the letter. Send the child on a bug hunt. Talk about the letters and the item.
Another educational game is sink-or-float. Gather small things from around the house and fill a tub with water. Ask your child if each item will sink or float. Then place the item in the water. If it does what they predict, they win.