I found this idea here: A Little Learning For Two: Cork and Popstick Rafts. and we decided to have a go !!
You can play with these little rafts even in the water, so it is a great fun.
These are the materials that you will need: Some corks (three for each raft), craft wood glue, I used bamboo skewers for the mast, two lollipop sticks for base of each raft ( I used colored ones) and a colored piece of paper for the sail.
Put the wood craft glue on the edges of the corks.
Then put the lollipop sticks so as to hold the corks together. Let it dry overnight. Now you attach the mast with the sail. I used bamboo skewers. Be careful because they have one very pointed side, but this makes it easy to pierce the cork and so hold up the mast.