All the recent newspaper articles about sledging over the Harbajahn case would be appropriate.
Fight scene between Helena and Hermia in Midsummer by Shakespeare.
Flushed Away- movie
Once Were Warriors
Gilmore Girls
You need to look for texts that use tight and effective dialogue. Don't need to be about sport.
Your purpose is to demonstrate how language and dialogue place characters in positions of power - or powerlessness.
The 'Dialogue' of the Bringing them Home Report etc- suggests how the language of the Stolen Generation and Government documents of the period perpetuated the dialogue- or conversations - that relegated people to positions of powerlessness through stereotyping. Watch some films like Crocodile Dundee and listen to how the dialogue is inflected with institutional racism even though, at times, it seems to be satirising the language itself. Be sophisticated- look for ways of linkng texts that show you understand the role of language in society.