RegularCapital.com has given us a title for the 22-minute LEGO special - the special will be called "LEGO Scooby-Doo: Knight Time Terror." The special will be in LEGO animation, just like the current LEGO shorts being released on YouTube. However, no date has been announced yet for the U.S., but the special will air October 24, 2015 in the UK. More info to come soon!
UPDATE: The article actually says it will air the week of the 24th, it does not specifically say the 24th.