From today you can buy single transfer tickets by SMS. Price is same - 20Kc. You just have to send SMS to the number 902 06 20 with the text DPT (it has to be in capital letters). You then receive SMS with ticket within two minutes. http://www.radio.cz/en/article/97845
Just saw that on iDNES - what a great idea. I sent an e-mail to my traveling partner - told him "leave it to the Czechs to do things right"