Sometimes when he is playing, he gets VERY frustrated because the toy doesn't do exactly what he wants it to do. (ie, blocks don't stay stacked after he put them where he wanted them) When something like this happens, he takes the block that fell and chunks it across the room out of anger. This is not a behavior that we want to see continue so we always remove him from the toys and talk to him about not throwing his toys. That worked for a little while but now it just seems to fire him up even more. So, we started using the time out mat.
I think it is actually working pretty well. AND, don't let that face fool you. He is there for less than a minute each time. The reason I feel like we may have stumbled across a tactic that works well for us is because yesterday, Jonah threw his bowl of cheerios after he tipped the bowl and some fell out. (I'm telling you, the kid is a perfectionist and does not handle things well when they don't go according to his plan!!!) Anyway, after he threw the bowl, he looked at me, put his head down and went and sat on the mat. HA! After he had been there 20 or 30 seconds, I sat next to him and told him why we don't throw things. Then, we got up and played...HAPPILY EVER AFTER! :-)