they might be time trials. i just remember when living there they had all sorts of cars dragging along eastern beach there. and wandered if they were still alowed to do that. it was all legal.
They still Happen. I went last year but it was mainly older cars pullin like 16's. Few quick bikes (running methanol)and team Honda had a van there and had a trail bike consistantly pull 11's. Other than that the model Sarah Jane was there doing a few runs in a porshe, there is a show and shine thing on the grass area with nice cars, it's still free (except for the pits $10 entry)and there is a stack of "talent" down there
They stopped it around 2000 i think it was for a year or two there because of the illegal activities taking place at night, but have bought it back.
check here for more
http://www.geelongspeedtrials.com/
Some original photos have not been recovered yet.