The one in Poland is fun. You can bar someone from working in the same field for quite some time but you must pay them 70-80% (I don't quite remember how much but something like that) of their annual salary during that time. Which means that most of the people proposing this kind of deal are clueless ans greedy businessmen who think they found a perfect leash for their employees but what's actually happening is that they find out far too late that it's binding them and not the employee.