Index: src/main/java/com/sun/grizzly/jruby/RailsAdapter.java
===================================================================
--- src/main/java/com/sun/grizzly/jruby/RailsAdapter.java	(revision 251)
+++ src/main/java/com/sun/grizzly/jruby/RailsAdapter.java	(working copy)
@@ -52,6 +52,7 @@
 import org.jruby.RubyException;
 import org.jruby.RubyIO;
 import org.jruby.RubyHash;
+import org.jruby.RubyThread;
 import org.jruby.exceptions.RaiseException;
 import org.jruby.javasupport.JavaEmbedUtils;
 import org.jruby.runtime.builtin.IRubyObject;
@@ -59,9 +60,9 @@
 import java.io.IOException;
 import java.io.OutputStream;
 import java.util.logging.Level;
-import java.util.logging.Logger;
 import java.util.Map;
 import java.util.HashMap;
+import java.util.WeakHashMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.locks.ReentrantLock;
 
@@ -72,6 +73,7 @@
  * @author Jean-Francois Arcand
  * @author Pramod Gopinath
  * @author Vivek Pandey
+ * @author Peter Williams
  */
 public class RailsAdapter extends GrizzlyAdapter {
 
@@ -198,9 +200,34 @@
         }
     }
 
+    private final Map<Ruby, WeakHashMap<Thread, RubyThread>> threadMaps =
+            new HashMap<Ruby, WeakHashMap<Thread, RubyThread>>();
 
+    private RubyThread getContextThread(Ruby runtime) {
+        RubyThread contextThread = null;
+        synchronized (threadMaps) {
+            WeakHashMap<Thread, RubyThread> threadMap = threadMaps.get(runtime);
+            if(threadMap != null) {
+                contextThread = threadMap.get(Thread.currentThread());
+            } else {
+                threadMap = new WeakHashMap<Thread, RubyThread>();
+                threadMaps.put(runtime, threadMap);
+            }
+
+            if(contextThread == null) {
+                contextThread = RubyThread.adopt(runtime.getThread(), Thread.currentThread());
+                threadMap.put(Thread.currentThread(), contextThread);
+            }
+        }
+        return contextThread;
+    }
+
     private void dispatchRailsRequest(Ruby runtime, GrizzlyRequest req, GrizzlyResponse res) throws IOException {
+        RubyThread oldContext = runtime.getThreadService().getMainThread();
         try {
+            RubyThread context = getContextThread(runtime);
+            runtime.getThreadService().setMainThread(context);
+            
             OutputStream os = res.getOutputStream();
 
             RubyIO iObj = new RubyIO(runtime, req.getInputStream());
@@ -219,6 +246,8 @@
             RubyException exception = e.getException();
             exception.printBacktrace(System.err);
             throw e;
+        } finally {
+            runtime.getThreadService().setMainThread(oldContext);
         }
     }