My attempt to make a PVC pipe bike rack was not successful. Even with securing the joints with PVC adhesive, the bike was just too heavy and it would tip over. And then it broke apart while being moved. Note: i used a different design than flybye's. specifically, i used:

http://www.instructables.com/id/Bike-Rack/

.. it may have only been unsuccessful because my measurements were off (long story) and the legs weren't as long as they were meant to be..