Replying to Ideas for DIY Pipe jam in UK

So hears the setup, we got a small hill (bout 6ft tall but 40 degree gradient), one newly built bungee chord (by greg), and a tonne of pipes that they did not at all steal from an industrial recycle bin.

We are doing all this on our university campus (where the little hill is)
and have a little bit of old carpet, and a workshop in one of the faculties that we can use for building the pipe supports.

Anyone done something like this before? If you have, how did you make your pipe support and what kinda features did you make using pipes? Also what do people think of a double barrel pipe?