Probably just an accidental slip - DrT thought by himself 'I'm thirsty' but instead he wrote 'On Thurday', because he was texting with his beer supplier as to when the next delivery was due while at the same time watching over the 1257AD forums section and so he accidentally posted the date for the next beer delivery into the forums instead of sending the message to his supplier while thinking all the time how thirsty he was, and when he saw all the jubilee on the forums he couldn't back up anymore because he didn't want to disappoint us. On reading this post in the forums, Kuauik got completely confused and thought by himself that DrT must have some kind of masterplan to release all the stuff until next thursday, so he jumped on the funny bandwagon.
But what began as a funny joke should soon end in a sad tragedy - the stupid beer supplier got the addresses of the two guys mixed up (Kuauik and DrT share the same beer supplier) and didn't deliver the beer to DrT but delivered it to Kuauik instead, of which Kuauik thought to be the long overdue present for all his hard texturing work and so he spent the next couple of days in sacred drunkeness. And the Friday theme came up because the stupid beer supplier did not only switch the addresses of the guys but also was one day too late with his delivery, which obviously was Friday as DrT had ordered the beer for Thursday. DrT was outrageously mad and therefore loudly shouted his complaints to the delivery guy and screamed that he wanted his beer NOOOW, while at the same time he got the message from Kuauik that under no circumstance would he be able to work until next Friday because he had gotten a surprise delivery of huge amounts of beer which would keep him busy until at least next Thurday or maybe next Friday - this was one of those rare moments when you could actually see tears appear in the eyes of DrT.
With no beer at his disposal DrT got almost mad, ate his cell phone and fell into a kind of beerless coma from which he woke up 3 days later and had completely forgotten everything about the masterplan he originally had, to bring out all the 1257AD stuff in time until "next random weekday". When he then tried to reach Kuauik, there was no one answering either the phone or mails, just one time somebody or something answered the phone and demonic noises could be heard such as "BLUUUUURB, whobbthegutter****no... moeBEEEEEEEEAAAAOOOOOUUUUURRR" upon which DrT then wisely decided to no further disturb Kuauiks experiments in otherworldly communications... and that's how the whole drawn-out 'next Thursday/Friday' topic came up.
Make sure to go early.
