diff --git a/zipline/algorithm.py b/zipline/algorithm.py
index bdd20ef4..46157010 100644
--- a/zipline/algorithm.py
+++ b/zipline/algorithm.py
@@ -125,6 +125,32 @@ class TradingAlgorithm(object):
         # call to user-defined constructor method
         self.initialize(*args, **kwargs)
 
+    def __repr__(self):
+        """
+        N.B. this does not yet represent a string that can be used
+        to instantiate an exact copy of an algorithm.
+
+        However, it is getting close, and provides some value as something
+        that can be inspected interactively.
+        """
+        return """
+{class_name}(
+    captial_base={capital_base}
+    sim_params={sim_params},
+    initialized={initialized},
+    slippage={slippage},
+    commission={commission},
+    blotter={blotter},
+    recorded_vars={recorded_vars})
+""".strip().format(class_name=self.__class__.__name__,
+                   capital_base=self.capital_base,
+                   sim_params=repr(self.sim_params),
+                   initialized=self.initialized,
+                   slippage=repr(self.slippage),
+                   commission=repr(self.commission),
+                   blotter=repr(self.blotter),
+                   recorded_vars=repr(self.recorded_vars))
+
     def _create_data_generator(self, source_filter, sim_params):
         """
         Create a merged data generator using the sources and
diff --git a/zipline/finance/blotter.py b/zipline/finance/blotter.py
index f3741e7b..6ba90bec 100644
--- a/zipline/finance/blotter.py
+++ b/zipline/finance/blotter.py
@@ -54,6 +54,21 @@ class Blotter(object):
         self.new_orders = []
         self.current_dt = None
 
+    def __repr__(self):
+        return """
+{class_name}(
+    transact_partial={transact_partial},
+    open_orders={open_orders},
+    orders={orders},
+    new_orders={new_orders},
+    current_dt={current_dt})
+""".strip().format(class_name=self.__class__.__name__,
+                   transact_partial=self.transact.args,
+                   open_orders=self.open_orders,
+                   orders=self.orders,
+                   new_orders=self.new_orders,
+                   current_dt=self.current_dt)
+
     def set_date(self, dt):
         self.current_dt = dt
 
diff --git a/zipline/finance/commission.py b/zipline/finance/commission.py
index 58a3df3e..057e84f4 100644
--- a/zipline/finance/commission.py
+++ b/zipline/finance/commission.py
@@ -28,6 +28,11 @@ class PerShare(object):
         """
         self.cost = float(cost)
 
+    def __repr__(self):
+        return "{class_name}(cost={cost})".format(
+            class_name=self.__class__.__name__,
+            cost=self.cost)
+
     def calculate(self, transaction):
         """
         returns a tuple of:
diff --git a/zipline/finance/slippage.py b/zipline/finance/slippage.py
index d0ce0bdf..879756ad 100644
--- a/zipline/finance/slippage.py
+++ b/zipline/finance/slippage.py
@@ -129,6 +129,15 @@ class VolumeShareSlippage(object):
         self.volume_limit = volume_limit
         self.price_impact = price_impact
 
+    def __repr__(self):
+        return """
+{class_name}(
+    volume_limit={volume_limit},
+    price_impact={price_impact})
+""".strip().format(class_name=self.__class__.__name__,
+                   volume_limit=self.volume_limit,
+                   price_impact=self.price_impact)
+
     def simulate(self, event, current_orders):
 
         dt = event.dt
diff --git a/zipline/finance/trading.py b/zipline/finance/trading.py
index 9292595f..b610ea65 100644
--- a/zipline/finance/trading.py
+++ b/zipline/finance/trading.py
@@ -299,11 +299,21 @@ class SimulationParameters(object):
         return len(self.trading_days)
 
     def __repr__(self):
-        return "%s(%r)" % (
-            self.__class__.__name__,
-            {'first_open': self.first_open,
-             'last_close': self.last_close
-             })
+        return """
+{class_name}(
+    period_start={period_start},
+    period_end={period_end},
+    capital_base={capital_base},
+    emission_rate={emission_rate},
+    first_open={first_open},
+    last_close={last_close})\
+""".format(class_name=self.__class__.__name__,
+           period_start=self.period_start,
+           period_end=self.period_end,
+           capital_base=self.capital_base,
+           emission_rate=self.emission_rate,
+           first_open=self.first_open,
+           last_close=self.last_close)
 
 
 class use_environment(object):