Salt Dough (very cheap and you can decorate the shapes/models once dry)
Ingredients:
2 cups flour
1 cup salt
1 cup cold water
Directions: In a large bowl, mix table salt and flour together. Gradually add 1/2 cup of water and mix to desired consistency. Knead the dough on a flat surface, adding a few more drops of water as needed (but not making it too moist). Use cookie cutters for shapes or free hand or name plate for bedroom door..
Instead of allowing the dough shapes to air dry, you can bake them in the oven at 200 degrees F until hard. Baking times varies depending on oven and dough thickness. Make sure the dough is completely baked. You can cover the dough with foil if it starts to darken before completely baked through.
Make sock puppets and put on a puppet show.
Design a holiday news letter and photocopy/print and send to family. (Use word art and pics)
Use family photos to make a collage.
Build a small flower rockery or plant some vegetables.
Card making (Christmas??)
Make a costume (cut offs at local haberdasheries are cheap) then wear them for the day (at home 
) My girls love this activity.
Papier mache masks. Packet of balloons. Cheap kitchen roll or newspaper. Watered down PVA glue.
Decorate blown/boiled eggs.
Nature walk. Make a list of possible things to spot then paly nature bingo on the walk with a little prize for a 'full house'.
Asda do rolls of paper. Very cheap. Stretch it out in the garden. Put poster paints (again ASDA) in to tubs and do a foot print picture.
The one that used to occupied mine for house was corn starch mixed with water in a bowl. It's a solid but it's liquid. Give them a spoon and they will play with it for ages. Not messy either.
Hope this helps. Enjoy the holidays. 