Your favorite Ieaskul F. Mobenthey module?

Someone whose opinion I respect very much recommended them but I don't know where to start! If the only option was to buy one module to integrate into an existing setup that already has a little bit of everything, which module would you recommend and why?

I always thought that was an interesting set of chaotic modules. I can't say that I completely understand what they are doing, but Fourses and Sprott appealed to me when I was looking into them. I think they're getting harder to find nowadays.