diff --git a/extensions/jython/module/MOD-INF/lib/jython-2.5.1.jar b/extensions/jython/module/MOD-INF/lib/jython-2.5.1.jar
new file mode 100644
index 000000000..56b9ce471
Binary files /dev/null and b/extensions/jython/module/MOD-INF/lib/jython-2.5.1.jar differ
diff --git a/extensions/jython/module/MOD-INF/module.properties b/extensions/jython/module/MOD-INF/module.properties
new file mode 100644
index 000000000..30937d12c
--- /dev/null
+++ b/extensions/jython/module/MOD-INF/module.properties
@@ -0,0 +1,3 @@
+description = Gridworks Jython Extension
+
+templating = false
diff --git a/extensions/jython/src/com/metaweb/gridworks/jython/JythonEvaluable.java b/extensions/jython/src/com/metaweb/gridworks/jython/JythonEvaluable.java
new file mode 100644
index 000000000..f73e76691
--- /dev/null
+++ b/extensions/jython/src/com/metaweb/gridworks/jython/JythonEvaluable.java
@@ -0,0 +1,132 @@
+package com.metaweb.gridworks.jython;
+
+import java.io.File;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Properties;
+
+import org.python.core.Py;
+import org.python.core.PyException;
+import org.python.core.PyFunction;
+import org.python.core.PyNone;
+import org.python.core.PyObject;
+import org.python.core.PyString;
+import org.python.util.PythonInterpreter;
+
+import com.metaweb.gridworks.expr.EvalError;
+import com.metaweb.gridworks.expr.Evaluable;
+import com.metaweb.gridworks.expr.HasFields;
+import com.metaweb.gridworks.expr.LanguageSpecificParser;
+import com.metaweb.gridworks.expr.ParsingException;
+
+public class JythonEvaluable implements Evaluable {
+    
+    static public LanguageSpecificParser createParser() {
+        return new LanguageSpecificParser() {
+            
+            @Override
+            public Evaluable parse(String s) throws ParsingException {
+                return new JythonEvaluable(s);
+            }
+        };
+    }
+    
+    private static final String s_functionName = "___temp___";
+    
+    private static PythonInterpreter _engine; 
+    
+    // FIXME(SM): this initialization logic depends on the fact that the JVM's 
+    // current working directory is the root of the Gridworks distributions
+    // or the development checkouts. While this works in practice, it would
+    // be preferable to have a more reliable address space, but since we
+    // don't have access to the servlet context from this class this is
+    // the best we can do for now.
+    static {
+        File libPath = new File("webapp/WEB-INF/lib/jython");
+        if (!libPath.exists() && !libPath.canRead()) {
+            libPath = new File("main/webapp/WEB-INF/lib/jython");
+            if (!libPath.exists() && !libPath.canRead()) {
+                libPath = null;
+            }
+        }
+        
+        if (libPath != null) {
+            Properties props = new Properties();
+            props.setProperty("python.path", libPath.getAbsolutePath());
+            PythonInterpreter.initialize(System.getProperties(), props, new String[] { "" });
+        }
+        
+        _engine = new PythonInterpreter();
+    }
+
+    public JythonEvaluable(String s) {
+        // indent and create a function out of the code
+        String[] lines = s.split("\r\n|\r|\n");
+        
+        StringBuffer sb = new StringBuffer(1024);
+        sb.append("def ");
+        sb.append(s_functionName);
+        sb.append("(value, cell, cells, row, rowIndex):");
+        for (int i = 0; i < lines.length; i++) {
+            sb.append("\n  ");
+            sb.append(lines[i]);
+        }
+
+        _engine.exec(sb.toString());
+    }
+    
+    public Object evaluate(Properties bindings) {
+        try {
+            // call the temporary PyFunction directly
+            Object result = ((PyFunction)_engine.get(s_functionName)).__call__(
+                new PyObject[] {
+                    Py.java2py( bindings.get("value") ),
+                    new JythonHasFieldsWrapper((HasFields) bindings.get("cell"), bindings),
+                    new JythonHasFieldsWrapper((HasFields) bindings.get("cells"), bindings),
+                    new JythonHasFieldsWrapper((HasFields) bindings.get("row"), bindings),
+                    Py.java2py( bindings.get("rowIndex") )
+                }
+            );
+
+            return unwrap(result);
+        } catch (PyException e) {
+            return new EvalError(e.getMessage());
+        }
+    }
+    
+    protected Object unwrap(Object result) {
+        if (result != null) {
+            if (result instanceof JythonObjectWrapper) {
+                return ((JythonObjectWrapper) result)._obj;
+            } else if (result instanceof JythonHasFieldsWrapper) {
+                return ((JythonHasFieldsWrapper) result)._obj;
+            } else if (result instanceof PyString) {
+                return ((PyString) result).asString();
+            } else if (result instanceof PyObject) {
+                return unwrap((PyObject) result);
+            }
+        }
+        
+        return result;      
+    }
+    
+    protected Object unwrap(PyObject po) {
+        if (po instanceof PyNone) {
+            return null;
+        } else if (po.isNumberType()) {
+            return po.asDouble();
+        } else if (po.isSequenceType()) {
+            Iterator<PyObject> i = po.asIterable().iterator();
+            
+            List<Object> list = new ArrayList<Object>();
+            while (i.hasNext()) {
+                list.add(unwrap((Object) i.next()));
+            }
+            
+            return list.toArray();
+        } else {
+            return po;
+        }
+    }
+}
diff --git a/extensions/jython/src/com/metaweb/gridworks/jython/JythonHasFieldsWrapper.java b/extensions/jython/src/com/metaweb/gridworks/jython/JythonHasFieldsWrapper.java
new file mode 100644
index 000000000..29d41af93
--- /dev/null
+++ b/extensions/jython/src/com/metaweb/gridworks/jython/JythonHasFieldsWrapper.java
@@ -0,0 +1,40 @@
+package com.metaweb.gridworks.jython;
+
+import java.util.Properties;
+
+import org.python.core.Py;
+import org.python.core.PyObject;
+
+import com.metaweb.gridworks.expr.HasFields;
+
+public class JythonHasFieldsWrapper extends PyObject {
+    private static final long serialVersionUID = -1275353513262385099L;
+
+    public HasFields _obj;
+
+    private Properties _bindings;
+
+    public JythonHasFieldsWrapper(HasFields obj, Properties bindings) {
+        _obj = obj;
+        _bindings = bindings;
+    }
+
+    public PyObject __finditem__(PyObject key) {
+        String k = (String) key.__tojava__(String.class);
+        Object v = _obj.getField(k, _bindings);
+        if (v != null) {
+            if (v instanceof PyObject) {
+                return (PyObject) v;
+            } else if (v instanceof HasFields) {
+                return new JythonHasFieldsWrapper((HasFields) v, _bindings);
+            } else if (Py.getAdapter().canAdapt(v)) {
+                return Py.java2py(v);
+            } else {
+                return new JythonObjectWrapper(v);
+            }
+        } else {
+            return null;
+        }
+    }
+
+}
diff --git a/extensions/jython/src/com/metaweb/gridworks/jython/JythonObjectWrapper.java b/extensions/jython/src/com/metaweb/gridworks/jython/JythonObjectWrapper.java
new file mode 100644
index 000000000..fb10bc70c
--- /dev/null
+++ b/extensions/jython/src/com/metaweb/gridworks/jython/JythonObjectWrapper.java
@@ -0,0 +1,17 @@
+package com.metaweb.gridworks.jython;
+
+import org.python.core.PyObject;
+
+public class JythonObjectWrapper extends PyObject {
+    private static final long serialVersionUID = -6608115027151667441L;
+
+    public Object _obj;
+
+    public JythonObjectWrapper(Object obj) {
+        _obj = obj;
+    }
+
+    public String toString() {
+        return _obj.getClass().getSimpleName();
+    }
+}