This was our first time. We've done this so far-
Hiding in DS's pants, while waving out of the drawer.
Made gingerbread men and left out smarties for decoration.
Painted everyone's nose red.
Put a Santa hat on the dogs, and was found sleeping next to the spaniel (we did it just before the DCs woke up, and made sure he was sleeping, so no chewing!)
Holding onto some helium balloons, about five of them or something, and then everyone having to jump around trying to get them (we decided to let them get on with it, and then I let DD2 climb on my shoulders to get him as he was tied to the cord things).
In the hamster ball.
On the toliet in the doll's house thing.
Looking at a photo on the camera (we took it of the DCs, even DD1 who's 12 and hasn't been a believer since about 5, where we'd all put Christmas hats of them on while they were watching TV and didn't realise until about five minutes later
) and with popcorn sprinkled around him, and he was trying to hold one near his mouth. DD2 and DS (and even DD1) loved that!
Had a icing bag thing next to six cupcakes, one of them half iced, with purple icing in the bag. Five all for us, the other one we left for Elf (and DH and I shared).