Having just had 2 primary school aged boys at home for 8 weeks over the summer/Christmas break, the following a few of the tricks that served me well. My boys are 9 and 6 years old, so the activities are probably better suited for younger kids rather than teenagers.
1. Treasure Hunt: I hit upon the simplest treasure hunt template, that can be used either outdoors or indoors. Get a sheet of paper and divide into 8 squares – easiest is to fold it half lengthways and then fold twice breadthways. In each square either write a random letter or a colour. The kids then have to find items that start with the particular letter or are that colour and then draw them in the square. You can make it as easy or complicated as you want and even allocate areas in the house where each kid can “hunt”. I have also sometimes, for older kids, put in simple maths, and then armed them with a ruler to find items that are of that length.
2. Chalk and Draw: A box of chalk goes a long way on a warm day with nothing much to do. Either get the kids to draw welcome messages to the driveway to the house, or do shadow drawing of each other. I, sometimes, get the kids to do alien drawings of themselves. One kid draws the outline of the other kid lying on the ground. The kid whose outline it is, then fills in the bits of the body. Being an alien the eyes and ears etc can go anywhere and can have as many. They can also draw antennae or zappers or contraptions and can keep them entertained for a while.
3. Cubby Houses: Good for cold or wet days – give the kids a bunch of blankets, pillows and cushions and let them create their own cubby/hideaway houses.
4. Cooking/Baking Together: Another good activity for wet days, is to bake together. My wife is a much better baker than me and includes the kids in making cookies, muffins, tarts etc. I usually get the kids involved in making meals – like putting the toppings on the pizza or helping mix and stir.
5.Board Games: Probably the most under utilised and under appreciated mode of entertainment in our house – but it can easily fill in a couple of hours. A game of monopoly or scrabble is entertaining for all.
6. Story Telling: This involves a lot of effort from the parents, however is a great way to spend a large part of the day. I get the kids to make up a story, one sentence at a time. I start it off with something innocuous like “Once upon a time there was a little boy called ZZZ”, and then the kids take over saying one sentence at a time. Usually I record the story on my phone and then after its told, I get them to draw pictures of the main bits of the story. Later in the day, we do a show for my wife, with the story being played from the phone and the kids holding up the pictures at the appropriate times.
7. Local Library: Australia is very lucky to have well stocked local public libraries all over the country. They are all free to join and have a collection of books for kids of all ages. A lot of them also run activities and story telling sessions during holidays.
8. Music and Dance: Probably the easiest of the lot, turn on some dancing music and put on your dancing shoes. Each child gets to dance solo and impress the others and at the end of each song, the best voted gets to pick the next song. The secondary advantage of this is that it tires out the kids as well.