python for sure.  you can use it with app engine, whereas ruby on the app engine jvm is less mature.<p>take a look at some source code here to help you get started:<p><a href="http://developeradvocate.appspot.com/id/1005/AppEngineBlog-(%22AEB%22)-Version-1.1.0-Released" rel="nofollow">http://developeradvocate.appspot.com/id/1005/AppEngineBlog-(...</a><p><a href="http://code.google.com/p/appengineblogsoftware/source/browse/#svn/trunk" rel="nofollow">http://code.google.com/p/appengineblogsoftware/source/browse...</a>