I have done donuts, M&Ms graph, and make a design for halloween with q-tips (30 of them). I can't think of anything fun for the 40th day which is tomorrow!
When I was in school we made posters (regular posterboard) where we would take things such as pennies, fruit loops, macaroni, and basically anything small enough and glue them in the shapes of the numbers (we only did this for the 100th day though...)
Do you mean which objects to use, or what to do with them? When you graph, are you showing the items out of 100? That is the concept you are laying the groundwork for (fractions, decimals). Little leaf or pumpkin-shaped stickers .... 40 leaves on a tree ....
I know, but couldn't you show stacks of tens, or groups of tens, out of 100. You wouldn't even have to mention the 100 until you get to that day. I just think the visual is important. It makes me crazy when I hear that teachers did all sorts of cutesy 100 day activities that don't relate to the whole point. Even at age 5 you can start to aim toward the bigger picture.
We color a number on the 100 grid chart everyday. Then they do the straw bundle thing and put the number above it.
We do that to every day. But we also, make a big deal when we get to the next 10 bundle. Tomorrow is the 40th day of school, so tomorrow Zero the Hero comes and leaves us a 40th day activity. Tomorrow is making a pattern with 40 fruit loops.
How about using a bagel to make a mini pizza for a snack? You could use 4 pepperoni to get the 4 in and the bagel for the 0. A fun activity for any 0 day - see where you end up in 40 steps (or whatever number) in each direction from your classroom or put 40 footprints down the hall to lead to a secret location - even more fun if you can send them 2 or 3 at a time and have another teacher at the other end so they have to follow the footprints on their own.
Each 10 I make a table with that number on it. So we just hit 40 so it had 40 squares. They had to color 1-9 whatever color but color 10 a new color. So then we counted by 10s. It was pretty simple. But I would also like to jazz up the 10th day!
Some great ideas on this site: http://sc.jeffco.k12.co.us/education/components/scrapbook/default.php?sectiondetailid=155369&sc_id=1198881534
I had 40 squares and they had to count out 40 fruit loops. Next I had them clue the 40 fruit loops on the 40s I had pasted to white paper.