This is easy if your child or children have a designated playroom. If not, wander around your house and think about any area that could be designated for children for a few months without much disruption. A corner of a dining room, part of a basement, or even the space between your family room and kitchen could work.
Start by creating a separate floor to define the space. An inexpensive throw rug or a carpet remnant in a color that contrasts with the floor would work well. Add in some useful furniture, such as a children’s play table or a coffee table with cushions around it. You can cover the table with a vinyl tablecloth to protect it from play activities. Extras such as bookshelves, bins, or even a small child’s tent can help to further delineate the space as for children. Posters or maps on a nearby wall add to the color and interest.
Once the space is set up, use it as a reward for finishing chores, homework, or as a source of interest during those long grey days when everyone is looking for something to do. Place a jar with suggestions for activities in it, with each child taking a turn selecting one. Spend an afternoon brainstorming ideas with your children, writing them on additional papers for the jar. Surprise them with special projects or tools. For example, one day they may find a box with different types of measuring tools in it, and instructions to determine what kinds of things each tool can measure well.
Create an imaginative space to compensate for the outdoor limitations, and help your children get through the winter without overdosing on TV or computer games.