Now here's where I really blow your brain: a Sequence is some stuff, in a particular order. What about the keyUp event? If I were to listen to that event, it might give me ['T','e','s','t'].
That too, is some stuff, in order. This means, that Events are Sequences. Which means, that all the cool stuff that can be done to Sequences, can be done to an Event too, which is exactly what the Reactive Extensions for JS from Microsoft does (disclaimer: I'm writing a book on this).
Haskell of course has this too, it's called the Continuation Monad.