NAB goes ex-dividend tomorrow for 90c fully franked. Currently it is trading at $23.90. Once it goes ex-dividend, all else being equal, it should trade tomorrow at $23, having dropped by the dividend amount.
I have taken the view that NAB will continue sliding over the next few weeks once the stock is ex-div. As a result, this afternoon I have sold a $22.51 call option for June. By selling this option, I have picked up a 95c premium today and I am still entitled to tomorrow's 90c dividend. If NAB is below $22.51 at expiry on 28 June, I keep the 95c premium. Therefore I have effectively created another dividend with my NAB shares!