I've been using Haskell to support my research sporadically over the years - developing a Library in Haskell to animate the Irish VDM formalism, used to reason about the external I/O behaviour of Haskell (and Clean) programs (see https://bitbucket.org/andrewbutterfield/irishvdm). A much bigger ongoingprject I started in 2007 is building a GUI-based theorem proving assistant (see http://www.scss.tcd.ie/Andrew.Butterfield/Saoithin/ and https://bitbucket.org/andrewbutterfield/saoithin)