We had great room parents for my daughter's kindergarten teacher. They gave all of the teachers a mini survey (favorite flower, favorite candy, hobbies and interests, etc), and then distributed the completed surveys to the room parent for each teacher. Based on the kindergarten teacher's responses, they arranged the following:
Monday: They asked each of the kids to bring in a lily (her favorite flower). Kids brought in things ranging from stargazer lillies to white lillies to lillies from flower gardens at home. One of the room moms brought an inexpensive vase to put them all in, and collected them on the playground before school. When the teacher came to the door to let the kids in at opening bell, she was presented with a wonderful boquet from the class. (The room moms had purchased some extra lillies for kids who forgot or didn't have a lilly to add).
Tuesday: Her favorite candy was M&M's, so they asked that each child bring a packet of M&M's to give to her.
Wednesday: Sticker Day: They asked each child to bring a sheet of stickers to replenish her supply that she uses on papers, artwork, etc.
Thursday: Book Day: Each child was asked to bring a book (new or gently used) to donate to the room's bookcase.
Friday: Portrait Day: The previous week, each child was given a sheet of construction paper to draw a picture of themselves with their teacher. They were also encouraged to write "Ms. Wright is a great teacher because........
and fill in the blank on the sheet. One of the moms got each of the pictures laminated, and had it assembled into a book for her. (Yes, this made the teacher cry.

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It took some work and planning on the room parents' part, and cooperation of the parents, but it was a lot of fun. Having a few extras of the asked for items helped all of the kids feel involved. I think the key was knowing about it well ahead of time instead of having a note come home saying "Send M&M's tomorrow".
Have a great time!