Bed time excuses

What do you do when a four year old keeps getting out of bed and asking for a hug, or a drink of water, or to goto the bathroom? This can go on for hours.
What do you do when a two year old doesn't want to goto bed in her crib, but throws a howling fit? Do you take her out and put her in a calm down spot, or make the crib the calm down spot. She wants to get out of the crib… but it is bedtime.