we took cupcakes but I did ask before I brought them in. I also took the teachers a cake and a thank you card for caring for DD for the first year of her life...
My dd's birthday is Halloween, so I ordered soft trick or treat bags from Oriental Trading and put a few cookies and Halloween themed toys that were age appropriate...rattles, etc....
other thngs that were sent home with DD - were rubber ducks, stuffed toys, etc.