In your Profile you can click on VG$ to see a balance to get an impression which action netted you how much. As I see it you get major VG-Cash for increasing your level (which is done by posting and stuff). Besides that you get VG$ for adding to the game database. And you can place more bets in the prediction league. I have old entries from 2008 with VG$ for forum activity, but this doesn't seem to be the case anymore, except the level-up bonus.
Besides that I don't know about anything, which doesn't mean there aren't other ways to net shiny VG-currency.
Thank you @Mnementh for the information, and specially thank you for creating these betting posts, I really enjoy them. My biggest concern is that I will soon go bankrupt and won't be able to participate in any future bets.
I wish that we had more short term bets, like this month totals or something like that, I think this is a great idea (betting) and hopefully with your posts it will grow a lot in the future.