http://eventful.com/brisbane/events/april
http://www.you.com.au/market-brisbane.html
http://www.brisbanepowerhouse.org/
Brisbane always has things happening ... markets at South Bank, and other places, music, entertainment, pubs. You can cruise the river, stopping off at a couple (at least) markets,
The Gold Coast has things that are more spread out ... OK if you have a car.