Our 4month old staffy pup barks at us whilst we are sitting on the couch after dinner when her energy levels are up again, so we have a bit of a wrestle and that useally sorts her out but sometimes she just barks and barks for no reason ( well i guess the reason is that she wants our attention). We have a bark busters toy which is a mesh bag filled with marbles (i think). if she is barking like mad we will throw this on the ground behind her to give her a fright and distract her, then we can ask for a sit command and then praise her and continue on from there.
good luck, have you got a food/treat ball, we give her her dry food in this and it takes her a while to get her whole meal and by the time she has done she has worn off some energy, good luck