I have a feeling that if your room is a little more tidy that housekeeping has the opportunity to do that kind of thing.
If you leave stuffed animals out, they will sometimes do funny things with them.
Also, at themouseforless.com you can print out envelopes for your tips with a thank you to mousekeeping.
In the parks you can pick up a badge if it's a special occasion - birthday, first trip, honeymoon, etc. You will get lots of good wishes.