We made salt dough and did the kids hand prints then painted the hand print to look like Santa. They used the rest of the dough to make whatever they wanted.
We also make snowflakes and hang them from the ceiling which they love!
Also printed of some colouring pages in a3 of Santa and elves, reindeer etc then coloured and cut them out and let the kids stick them on the walls.
We normally keep a really neat, everything has its place, type home so letting the kids go crazy with art everywhere is a real treat for them!
One of my daughters is very creative and loves her craft so I just let her decide what she wants to make, then the others usually join in.