Father Christmas left "Fabulous Origami Boxes" by Tomoko Fuse for me this year - a lot of fun, highly recommended. I found I wanted to line the hexagon box though and a cut hexagon didn't look right, so I came up with this folded hexagon which if made with the same sized paper as the box or just a little smaller, locks perfectly into the bottom of Tomoko's hexagon box. Also it doesn't have any creases to spoil the look. Give it a go, here's the pdf diagram.
hexagon.pdf (17.87 kb)