Yeah - it's kinda given that at an Aussie party you are going to drink! But people are a lot more understanding about the drink/driving thing and so if you say you're the Designated Driver (even if you're not) they usually respect that. The other excuse is to say you're on medication but it irritates me that you have to think of excuses to explain why you are not drinking for whatever reason. I have a friend who's a recovering alcholic (3 years sober, yay!) and he just tells people he's an alkie and they are usually so shocked at his honesty they forget to pour him a beer. But there are still some morons out there who will say "oh go on, just a small one".