Safe Haskell and the Continuation monad

Details
Summary
We have two exciting presentations this time around: Ryan Orendorff will walk us through the Continuation monad, and Kristen Kozak will teach us about Safe Haskell.
The Continuation monad, otherwise known as "mother of all monads", can be used to achieve advanced flow control, turn our code "inside-out", help solve "callback hell", and more.
Safe Haskell, an extension to the Haskell language, makes the types of programs trustable by allowing unsafe code to be securely included in trusted code by restricting the features available to it.
Have you used Safe Haskell or the Continuation monad in your projects? How have they helped you secure or structure your code?
References
• http://blog.sigfpe.com/2008/12/mother-of-all-monads.html
• https://wiki.haskell.org/All_About_Monads#The_Continuation_monad
• http://okmij.org/ftp/continuations/#tutorial
• http://hackage.haskell.org/package/transformers-0.4.2.0/docs/Control-Monad-Trans-Cont.html
• https://ghc.haskell.org/trac/ghc/wiki/SafeHaskell
• https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/safe-haskell.html

Safe Haskell and the Continuation monad