Building forts with couch cushions, pillows, chairs, tables and lots and lots of blankets is a classic childhood indoor activity — but can also be fun as an adult. The best part is making it all up as you go along but here are a few basic pointers. furniture and cushions that are already in the room, pillows, blankets, sheets, extra chairs, heavy books and/or clothespins string of fairy lights, flashlights, snacks, portable TV or viewing access to the TV, laptop, books to read 1.