We had a 2hr delay leaving JNB last year- engineers had flattened batteries on 744 and they were arranging to borrow some from SAA I think- Capt, F/O and a couple of cabin crew came up to gate lounge. Capt made a PA explaining the problem,and then he and the lady F/O walked around chatting to pax.Cabin crew had one of the bar boxes of soft drinks and snacks, which they proceeded to hand out. It was very well received by the pax ,very good handling of delay.