diff --git a/mongoqueue/mongoqueue.py b/mongoqueue/mongoqueue.py
index 65a9022..c561b64 100644
--- a/mongoqueue/mongoqueue.py
+++ b/mongoqueue/mongoqueue.py
@@ -21,6 +21,8 @@
 
 DEFAULT_INSERT = {
     "priority": 0,
+    "time": None,
+    "period": 0,
     "attempts": 0,
     "locked_by": None,
     "locked_at": None,
@@ -70,27 +72,84 @@ def repair(self):
                 "$inc": {"attempts": 1}}
         )
 
-    def put(self, payload, priority=0):
+    def put(self, payload, priority=0, time=None, period=None):
         """Place a job into the queue
         """
         job = dict(DEFAULT_INSERT)
         job['priority'] = priority
+        job['time'] = time
+        # Store period as an integer representing the number of seconds
+        # because BSON format doesn't support timedelta
+        if period and type(period) == timedelta:
+            job['period'] = period.total_seconds()
         job['payload'] = payload
+        if self.is_dupe(job):
+            return
         return self.collection.insert(job)
 
+    def is_dupe(self, job):
+        jobs = self.collection.find({
+            'payload': job['payload'],
+            'time': job['time'],
+            'period': job['period'],
+            'attempts': 0},
+            limit=1
+        )
+        for job in jobs:
+            if job:
+                return True
+        return False
+
     def next(self):
-        return self._wrap_one(self.collection.find_and_modify(
-            query={"locked_by": None,
-                   "locked_at": None,
-                   "attempts": {"$lt": self.max_attempts}},
-            update={"$set": {"attempts": 1,
-                             "locked_by": self.consumer_id,
-                             "locked_at": datetime.now()}},
-            sort=[('priority', pymongo.DESCENDING)],
-            new=1,
+        scheduled_job = self.next_scheduled_job()
+        free_job = self.next_free_job()
+        next_job = None
+
+        if scheduled_job and scheduled_job['time'] < datetime.utcnow():
+            next_job = scheduled_job
+        else:
+            next_job = free_job
+
+        return self._wrap_one(self.collection.find_and_modify({
+                "_id": next_job["_id"]
+            },
+            update={
+                    "$set": {
+                        "locked_by": self.consumer_id,
+                        "locked_at": datetime.now()
+                    }},
+            new=True,
             limit=1
         ))
 
+    def next_scheduled_job(self):
+        jobs = self.collection.find({
+                "locked_by": None,
+                "locked_at": None,
+                "time": {"$ne": None},
+                "attempts": {"$lt": self.max_attempts}
+            },
+            sort=[('time', pymongo.ASCENDING)],
+            limit=1
+        )
+        for job in jobs:
+            return job
+        return None
+
+    def next_free_job(self):
+        jobs = self.collection.find({
+                "locked_by": None,
+                "locked_at": None,
+                "time": None,
+                "attempts": {"$lt": self.max_attempts}
+            },
+            sort=[('priority', pymongo.DESCENDING)],
+            limit=1
+        )
+        for job in jobs:
+            return job
+        return None
+
     def _jobs(self):
         return self.collection.find(
             query={"locked_by": None,
@@ -153,6 +212,17 @@ def job_id(self):
     def complete(self):
         """Job has been completed.
         """
+        if self._data['period']:
+            updated_time = self._data['time'] + timedelta(seconds=self._data['period'])
+
+            return self._queue.collection.find_and_modify(
+                {"_id": self.job_id, "locked_by": self._queue.consumer_id},
+                update={"$set":{
+                    "locked_by": None,
+                    "locked_at": None,
+                    "time": updated_time
+                }})
+
         return self._queue.collection.find_and_modify(
             {"_id": self.job_id, "locked_by": self._queue.consumer_id},
             remove=True)
@@ -166,6 +236,15 @@ def error(self, message=None):
                 "locked_by": None, "locked_at": None, "last_error": message},
                 "$inc": {"attempts": 1}})
 
+        if self._data['attempts'] == self._queue.max_attempts - 1 and self._data['period']:
+            updated_time = self._data['time'] + timedelta(seconds=self._data['period'])
+
+            self._queue.put(self._data['payload'],
+                priority=self._data['priority'],
+                time=updated_time,
+                period=timedelta(seconds=self._data['period']))
+
+
     def progress(self, count=0):
         """Note progress on a long running task.
         """
@@ -181,6 +260,13 @@ def release(self):
             update={"$set": {"locked_by": None, "locked_at": None},
                     "$inc": {"attempts": 1}})
 
+    def abort(self):
+        """Intentionally terminate execution of a job, and remove it from the queue
+        """
+        return self._queue.collection.find_and_modify(
+            {"_id": self.job_id, "locked_by": self._queue.consumer_id},
+            remove=True)
+
     ## Context Manager support
 
     def __enter__(self):
@@ -192,3 +278,4 @@ def __exit__(self, type, value, tb):
         else:
             error = traceback.format_exc()
             self.error(error)
+            return True
diff --git a/mongoqueue/test.py b/mongoqueue/test.py
index dfbdb3a..d6f4db4 100644
--- a/mongoqueue/test.py
+++ b/mongoqueue/test.py
@@ -111,6 +111,20 @@ def test_release(self):
         job = self.queue.next()
         self.assert_job_equal(job, data)
 
+    def test_max_attempts(self):
+        data = {"context_id": "alpha",
+                "ts": time.time()}
+        self.queue.put(dict(data))
+        attempts = 0
+        for i in xrange(0, self.queue.max_attempts):
+            job = self.queue.next()
+            if not job:
+                break
+            with job:
+                attempts += 1
+                raise Exception()
+        self.assertEqual(attempts, self.queue.max_attempts)
+
     def test_error(self):
         pass
 
diff --git a/setup.py b/setup.py
index a7e7ba4..468a596 100644
--- a/setup.py
+++ b/setup.py
@@ -1,7 +1,7 @@
 from setuptools import setup, find_packages
 
 setup(name='mongoqueue',
-      version="0.7.2",
+      version="0.7.3",
       classifiers=[
           'Intended Audience :: Developers',
           'Programming Language :: Python',