School holiday ideas and projects

Hey, I'm trying to come up with some ideas for my dd (11years) and her cousin (6 years) to do together on the holidays.
Would like some 'project' ideas that they can do when they are both at my place, so like an ongoing thing that they can come back to each few days.
I need some ideas of things they can do themselves as I have a lot of work to do from home these holidays with setting up a new business
I'm happy to take time out to help them, but would like some things for them to do that they can work on themselves.
Throw some wonderful creative ideas at me!!! thanks :)

Learn to knit or crochet, do a scarf or granny squares rug. If that's beyond them, some French knitting or even Pompom making (different sizes tied together with bobbly eyes to make animals etc).

Get them set up with nail art supplies (cheapest if ordered online). Find some blogs and you tubes, this one has endless entertainment potential.

In a similar vein, set them up with clips etc & point them towards some how to hair braiding type tutorials. They can have endless fun constructing complex hairstyles.

Mosaic project, eg, stepping stones for garden or number thingo for front of your house.

Set them up with some smash book or scrap book supplies. Suggest some themes to get them started.

Give them some plasticine so they can make a stop motion animation.

Get all their school books/stationery out and stickers/pictures - they can label/decorate their own supplies.

Simple cooking is good at this age. Let them read and work out the recipes themselves... A little supervision but mostly just let them go for it.

We had an awesome time with fabric pens making Xmas presents. We did white aprons & tea towels, fuilled them completely with doodles and pictures. Kids could use white sand shoes, pillowcases, hats, calico teddies, placemats, whatever takes your fancy or you can get cheaply.

Some great idea's there!!! Thanks :)
Love the mosaic idea!!