Yeah that age pill thing came and went, but it raised interesting moral issues regarding incarceration.
Just imagine, instead of serving your whole time, you just age it instead. This questions the purpose to prisons, whether it is for reform or for punishment.
With first class writing and acting, this is one of those rare shows you can go back to and enjoy again and again. I've got the first 3 seasons on DVD and the 4th (twice as many episodes as the rest) on video.