One year I made a great project with "harvest colored" construction paper (red, brown, etc), glue, string and assorted beans, spices, seeds (on hand or from nature). It was really easy and I'm afraid my directions below will mess you up - so the big picture is that I folded the paper and on each piece wrote a letter of "Happy Thanksgiving" in glue, then sprinkled the seeds or spices or beans on the glue. I strung it up and hung it up and it was GREAT. It lasted 3 years too!!
I folded the paper so it came to a point (about 2/3 of the way down the paper, using the short edge), then folded the long sides back to the middle. The top (opposite the point) I folded about 2 inches. Then on each piece I wrote a letter in glue (e.g, "T" and "H") and then sprinkled some light object on it (lentils, spices, etc). After it dried, I spread out a length of yarn and put the letters in order with the top fold over the yarn, and taped the fold to the back. Voila!
If you have cement or a hard clay, another easy project to do is to take a flower pot and put a stick in that hard stuff. Then you decorate the stick (for Thanksgiving paper leaves with reasons to be thankful; for Halloween ghosts and witches). You might be able to do it with some tape and sand or rocks too.