Mind Jar -- meditation tool for all ages: "when stressed, overwhelmed, or upset, imagine the glitter as your thoughts/emotions. when you shake the jar, imagine your head full of whirling thoughts/emotions. then watch as they slowly settle together, and you calm down."
This is a calming jar. Instead of timers for time out. Use this. Shake it up, and place it in front of your LO. Explain to them that when it's all shook up, that's how their mind is when they are angry/frustrated/over-whelmed. That sitting there watching all the glitter fall to the bottom will help them calm down, and when they calmed down they can see clearly again.