Pretending to sleep
My first kid at 4yrs old pretended to sleep in the car one time so we would carry her in. My husband said he thought she was faking so I told him to lift her arm in the air to test her, if she's really asleep it will stay up in the air instead of falling down. It's so hard to keep the laughter down when her arm stays up we are never annoyed about her wanting to be carried again and she gets the extra cuddle time.
She's now 5 and her little 2yr old sister has started to try to get in on this trick. She will squeeze her eyes closed tight and say "test my arm, it will stay up cause I'm sleeping" and then after the test results are seen she drops her arm and nods when you say "oh she's really sleeping too!" Big sisters mouth will twitch in a smile and they both get carried inside the house where 2yr old instantly wakes up and 5yr old keys out a silly yawn and rubs her eyes.
I love that they think they are getting away with something and it makes us parents smile too.