All year long our kids leave toys and things throughout the house and we end up picking them up. To help our kids and our wallet we collect them and place them beyond the reach of the kids and hold them till Christmas time.
The large box is then wrapped with all the kids' names. The now actually ask for their toys back as part of their Christmas list. An added bonus is that some lovely toys are forgotten and become more interesting again when regifted to the child that owns them.