Can I recommend Kidzworld in Alexandria. As well as the usual soft play stuff, they've got bouncy castle, wee fast bikes, and gym equipment, and cafe for us to get coffee and stuff from while kids tire themselves out (in fact if they're being really awful - the cafe even has a full bar license!!!)
And just to finish my sales pitch - they have a Family Night every Friday night 5.30pm - 8pm. Entry is free - so the kids can play, there's mini disco, karaoke, and loads of other stuff for them to do while mum & dad can relax with a drink and something to eat from evening specials board.
In addition you can also win a months free entry to Kidzworld for 2 adults and 2 children if you go and register on their new website (from the home page click on the link for competitions.)