Feedback Requested on Event-Based Library

I just posted a new event-based library, and I would love some feedback on it. The library is called “Eventually” and you can find it here:

http://github.com/johnnyb/Eventually

I put a little tutorial video here:

https://www.youtube.com/watch?v=QvQAl-zbiCI

I would love to know what people think about it, and how I might improve it.