We always do a Christmas shoebox, and buy things to put in, but also ask the children if they want to put some of their toys in.
Ds2 is 5, but still plays a lot with his wooden railway, and it really is his "Number One Toy". He made up a small figure-of-8 layout, and then carefully packed it into the box, with one of his favourite engines and two trucks. He solemnly told me that if he was poor and didn't have many toys, this is what he would most like to have, so that's why he wanted to send it.
I know he has loads of toys, and he won't really miss it. But I am so proud of his generosity and thoughtfulness.