Best to keep them at $0 value. Even when there is an emanant IPO there are so many variables that can keep the options at $0 that it's best to look at them as having no value. To top that off, all cases are different so your best bet is to consult an experienced attorney. You might want to get together with others in the same situation so you can share the costs. But don't make a general announcement. Your bosses might not like it.

Remember, companies are looking at their interest 1st, yours second, if that. So chances are that whatever happens, the company will come out ahead.