I found $150 on exiting the toilets, and handed it to the receptionist. She sent out an email to the whole office, and the owner was found.
From where I come from, if you lose something, and someone else finds it, and returns it, you owe him 10% of the value.
Well, this guy did not even thank me.
Although I know it's illegal and partly immoral, next time I find money in the office, I'm even more tempted to keep it.