My boys took my best quality Egyptian cotton white sheet and sellotaped it to the picture rail on the playroom wall
They moved all the furniture around and set it up as a home cinema, made posters, and agreed job descriptions for different responsibilities.
I didn't think it would work very well - even though the sheet had been beautifully ironed - but we decided to humour them.
They got dh to set up his laptop and projector, and we got popcorn and brownies, and all settled down to watch a movie together...
It was great fun: I really enjoyed it. The picture and sound quality was pretty good, and it was a great activity for a wet Sunday afternoon.
Needless to say the boys were plotting to charge their friends to come round, until I pointed out that it is actually illegal