diff --git a/etc/spack/packages.yaml b/etc/spack/packages.yaml
index e89562e8d2..abdd888351 100644
--- a/etc/spack/packages.yaml
+++ b/etc/spack/packages.yaml
@@ -3,6 +3,6 @@ packages:
     paths:
       intelmpi@4.1.0%gcc@4.4.7 arch=linux-x86_64: /software/compilers/intel/13.0/impi/4.1.0.024/intel64
     buildable: False
-  all:
-    providers:
-      mpi: [intelmpi, openmpi]
+#  all:
+#    providers:
+#      mpi: [intelmpi]
diff --git a/var/spack/repos/builtin/packages/intelmpi/package.py b/var/spack/repos/builtin/packages/intelmpi/package.py
index 6750ee695a..5a9cdcdbf1 100644
--- a/var/spack/repos/builtin/packages/intelmpi/package.py
+++ b/var/spack/repos/builtin/packages/intelmpi/package.py
@@ -37,16 +37,19 @@ class Intelmpi(Package):
 
     def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
         spack_env.set('MPICC',  join_path(self.prefix.bin, 'mpicc'))
-        spack_env.set('MPICXX', join_path(self.prefix.bin, 'mpic++'))
+        spack_env.set('MPICXX', join_path(self.prefix.bin, 'mpicxx'))
         spack_env.set('MPIF77', join_path(self.prefix.bin, 'mpif77'))
         spack_env.set('MPIF90', join_path(self.prefix.bin, 'mpif90'))
+        # NOTE: Need to find a better way of setting this compiler argument
+        # which is only required when building packages with intelmpi.
+        spack_env.set('CXXFLAGS', '-DMPICH_IGNORE_CXX_SEEK')
 
     def setup_dependent_package(self, module, dep_spec):
         self.spec.mpicc = join_path(self.prefix.bin, 'mpicc')
-        self.spec.mpicxx = join_path(self.prefix.bin, 'mpic++')
+        self.spec.mpicxx = join_path(self.prefix.bin, 'mpicxx')
         self.spec.mpifc = join_path(self.prefix.bin, 'mpif90')
         self.spec.mpif77 = join_path(self.prefix.bin, 'mpif77')
-        self.spec.cppflags = '-DMPICH_IGNORE_CXX_SEEK'
+#        self.spec.cxxflags = '-DMPICH_IGNORE_CXX_SEEK'
 
 #    def install(self, spec, prefix):
 #        configure("--prefix=%s" % prefix)
diff --git a/var/spack/repos/builtin/packages/plumed/package.py b/var/spack/repos/builtin/packages/plumed/package.py
index 023de82b9b..b1e74c5827 100644
--- a/var/spack/repos/builtin/packages/plumed/package.py
+++ b/var/spack/repos/builtin/packages/plumed/package.py
@@ -30,13 +30,15 @@ class Plumed(Package):
        molecular systems which works together with some of the most popular
        molecular dynamics engines."""
 
-    # FIXME: Add a proper url for your package's homepage here.
+    # PLUMED homepage. The source is available on github.
     homepage = "http://www.plumed.org/home"
     url      = "https://github.com/plumed/plumed2"
 
     version('2.2.3', git="https://github.com/plumed/plumed2.git", tag='v2.2.3')
 
-    # Variants
+    # Variants. PLUMED by default builds a number of optional modules.
+    # The ones listed here are not built by default for various reasons,
+    # such as stability, lack of testing, or lack of demand.
     variant('crystallization', default=False,
             description='Build support for optional crystallization module.')
     variant('imd', default=False,
@@ -46,15 +48,14 @@ class Plumed(Package):
     variant('mpi', default=False,
             description='Enable MPI support.')
 
-    # Dependencies
+    # Dependencies. LAPACK and BLAS are recommended but not essential.
     depends_on("mpi", when="+mpi")
     depends_on("netlib-lapack")
     depends_on("openblas")
 
     def install(self, spec, prefix):
-        configure("--prefix=" + prefix)
-#                  "--enable-mpi",
-#                  "-enable-modules=crystallization")
+        # Prefix is the only compulsory argument.
+        config_args = ["--prefix=" + prefix]
 
         # Construct list of optional modules
         module_opts=[]
@@ -64,19 +65,28 @@ def install(self, spec, prefix):
             '+manyrestraints' if '+manyrestraints' in spec else '-manyrestraints'
         ])
 
-        # Add optional arguments based on specs and variants
-#        config_args.extend([
-            # Modules
-#            "--enable-modules=%s" % "".join(module_opts) if module_opts is not None,
-#            "--enable-mpi" if '+mpi' in spec
-#        ])
-
-        if modules_opts:
+        # If we have specified any optional modules then add the argument ro
+        # enable or disable them.
+        if module_opts:
             config_args.extend(["--enable-modules=%s" % "".join(module_opts)])
 
-        config_args.extend([
-            "--enable-mpi" if '+mpi' in spec else "--disable-mpi"
-        ])
+        # If using MPI then ensure the correct compiler wrapper is used.
+        if '+mpi' in spec:
+            config_args.extend([
+                "--enable-mpi",
+                "CC=%s" % self.spec['mpi'].mpicc,
+                "CXX=%s" % self.spec['mpi'].mpicxx,
+                "FC=%s" % self.spec['mpi'].mpifc,
+                "F77=%s" % self.spec['mpi'].mpif77
+            ])
+
+        # Add remaining variant flags.
+#        config_args.extend([
+#            "--enable-mpi" if '+mpi' in spec else "--disable-mpi"
+#        ])
+
+        # Configure
+        configure(*config_args)
 
         make()
         make("install")