I would do the old trick when my cat yawns to stick my finger in his mouth – dunno why I do it, I guess it's just funny to see his expression when boom!, suddenly finger.
So the other day he is sitting on my lap, and I yawn, he wakes up and does a stretch, perfectly putting his paw in my mouth – boom! suddenly paw.
Still no idea if by accident or if planned. His smug expression afterwards makes me lean towards the latter.
My dog knows my caller ID. I sometimes need to call home from my cell, and our home phone "speaks" the incoming call's caller ID. The only time my dog ever howls is when I call and the answering machine says my ID. She's done it when my mom is off somewhere else in the house and can't hear the phone ringing. She doesn't do it for any other phone call, even if I'm not home. I also tried calling while I'm still home to see if I can get her to howl, but she just looks at me like I'm an idiot.
My dog also has two bowls: one for food and one for water. Whenever I give her some crushed ice to lick in the water bowl, she'll pick up chunks of the ice and put them in the food bowl instead. Apparently, solids = food bowl, even if said solids turn into water.