fine!
When my brother and I were little, my mother decided we were using too much ‘bad language’ — we were calling each other ‘stupid’ and ‘moron’ – and to curb our tongues, she instituted a fine. We were to drop 25 paise into a gulak for adjectives like that, 50 paise for using sh!#. These colorful gulaks in Mazjid Moth, Dilli, reminded me of that failed behavioural modification experiment 
Were this gulak thing instituted in our house again, all of us would be contributing quite a bit — parents included! Hmm, maybe we could use the spoils to get some good PG-13 DVD’s … 