Words for "thing"? Different usages? 办法说“事情“或者”东西“？用的时候是一样的吗？
「事情」refers to an event or situation. I wouldn't translate it as thing; the only situation where thing is an acceptable translation is something like

他辦事情去了
He went to take care of something

But something could have easily been substituted with a situation.

I disagree with the other answers here; there are several things that are abstract but  which can be referred to as a「東西」.

感情是個很奇怪的東西
Emotions are a very strange thing

You cannot replace this with「感情是個奇怪的事情」, which doesn't make sense.