Ohhh, man, I have so many! A lot have been mentioned already.

Singing - You are my sunshine is my fave.
Find some silly sort of distraction for yourself, like swaying, and counting each sway until you get to 100 or similar. Makes the time pass faster.
Count out loud very softly and slowly.

For bigger kids:
Stroke the forehead/eyebrows in a directiont hat makes your hand shadow their eyes.
Close your own eyes.
Stroke downwards along their legs.
Hold their hand and stroke their back at the same time.

I think the most important thing is to just be patient. Go until you just think you can't do it any more, then go a little bit further.