What's the "Rails way" to deal with a large number of controllers?

In my Rails application the controllers are starting to pile up (> 30).

Would it be Java, I'd started to create sub-packages long ago, but I'm a little hesitant here. I already have a User and an Admin namespace but I'm not sure if it is good to create a finer namespace structure, especially considering maintainability.

What's the "Rails way" in this case?

• Just have a more or less flat controller structure?
• Or is it better to generously bundle controllers into namespaces/modules?

Thanks in advance.