Time outs are okay but the one thing I would avoid is putting them in their crib for timeout. Children will learn to associate their bed with punishment. Find a special place for punishment unless you want them sleeping with you???
My 2 yr old once got up out of bed, went into the kitchen, snagged a potato, climbed up on a chair then the counter(potato in hand), grabbed a knife from the block, cut the potato in half and burned it up in the microwave. Then he went back to bed.