How about the following ::
(1) Project Euler
(2) Try to extend a sequence that is 'difficult' to extend from the OEIS
(3) Find an existing program in C/C++/Java/C# and rewrite it in python [you learn a bit more about other langs and improve your python]
(4) Bug hunting/bug fixes for the open source project(s) you would most like to join
Most every open source project welcomes you to find and make them aware of bugs - and you will start to build a positive reputation in their forum/mailing list AND gain more depth of experience with the project
(5) Write a board game app - or a variation on the rules for one [3 dimensional othello/reversi and devise appropriate rules? Alice chess or any other chess variant? (i mention these because they are well down my 96,378 item deep to-do list lol)]
C++ya,
xkey