The Haskell Tool Stack stack is a cross-platform program for developing Haskell projects. It is aimed at Haskellers both new and experienced.

Idris is a new compiled dependently typed language with an FFI and multiple backends (LLVM, Javascript, etc.)

Haskell build system and commandline interface to Hackage

The PureScript compiler and libraries have plenty of open issues which can be tackled by Haskell beginners.

A small strongly, statically typed language that compiles to Javascript. Similar to Haskell but with a more flexible record system and extensible effects.