Rocket ride - what/where/when?

[hitch]

i rode across the Fairfield pipe bridges one night late last year, and there were a few guys congregating at the end of the bridge, and i heard one of them say " are you here for the rocket ride?" - or at least something like that. then I passed a whole lot of other people converging. I assume it was an organised ride along the Yarra trails. does anyone know what this might have been? who organises it? when it's on etc?

[hitch]

Hmmmm... First rule of rocket ride is you don't talk about rocket ride?

Ok, taking a different tact, does anyone know of a regular ride along the Yarra on a weeknight evening/morning?