When I was in 3rd grade and went to WDW my mother decided to do a "cute" note as well. I can't remeber exactly but it was along this line...
Please excuse ________ from school for the week of _________. She will be travelling around the world, shooting into space, being chased by dinosaurs, shrunken to the size of a field mouse and dining with variuos rodents and waterfowl.
We would be happy to take along some assignments to complete between splashes, shrieks, squeals and laughs and will have a wonderful report on our adventures when we return.
signed...mom and dad
NOW...the (perhaps unwanted) advice. i always had some assignments to take with me which we did in the hotel room for 1/2 hour before bed on most but not all nights PLUS we did our own special assignments so we could have a little report to show the teacher when we got back just to help make up for the missed time. Some examples are...
ABC photo book of Disney (example...Aladdins flying carpets, Big Al at the Jamboree, China pavilion.....etc)
A project on a country at Epcot (what each building represents, a report on the food, how the souvenirs represent the country and a short interview with a cast member from the country)
A Disney Zoology report...collect as many photos of animals as you can and put them together in a book with their name, a brief description and where the animal was found.
These can be adjusted for younger or older children and the teachers were always impressed at the extra effort and tended to overlook some of the stuff we missed. Also having a Disney project is fun!!!! It's great for the whole family to try to get a photo of something from A to Z (you get really creative photos and see Disney in a different way)
Hope this helps...good luck!
El.