Try Haskell at tryhaskell.org!
Get the Git version of Mueval from here: https://github.com/gwern/mueval It has some additions that tryhaskell needs.
Build tryhaskell
$ cabal sandbox init
$ cabal install --only-dependencies
$ cabal build
$ cabal sandbox hc-pkg hide monads-tf
Start tryhaskell, hosted at http://127.0.0.1:4001/
$ env PATH=./.cabal-sandbox/bin:$PATH \
GHC_PACKAGE_PATH=$(cabal sandbox hc-pkg list | grep '^/.*\.cabal-sandbox') \
./dist/build/tryhaskell/tryhaskell
tryhaskell does not currently support any command line arguments or configuration files.