diff --git a/IPython/demo.py b/IPython/demo.py
index 77cb546..7ca26e9 100644
--- a/IPython/demo.py
+++ b/IPython/demo.py
@@ -242,6 +242,7 @@ class Demo:
         print marquee('<%s> block # %s (%s remaining)' %
                       (self.fname,index,self.nblocks-index-1))
         print self.src_blocks_colored[index],
+        sys.stdout.flush()
 
     def show_all(self):
         """Show entire demo on screen, block by block"""
@@ -257,6 +258,7 @@ class Demo:
                 print marquee('<%s> block # %s (%s remaining)' %
                               (fname,index,nblocks-index-1))
             print block,
+        sys.stdout.flush()
             
     def __call__(self,index=None):
         """run a block of the demo.
diff --git a/doc/ChangeLog b/doc/ChangeLog
index fe771b5..8b6a9ed 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,3 +1,8 @@
+2006-01-25  Fernando Perez  <Fernando.Perez@colorado.edu>
+
+	* IPython/demo.py (Demo.show): Flush stdout after each block, so
+	computationally intensive blocks don't appear to stall the demo.
+
 2006-01-24  Ville Vainio  <vivainio@gmail.com>  
 
 	* iplib.py, hooks.py: 'result_display' hook can return a non-None