Hi Abby,
An Issan 'ceileidh' is when all they all go back to their home town in Issan usually around the festivals such as Songhram, Bhudda's Birthday, etc. The last one I was at was a local festival in a small town near Khon Kaen - they start with an early morning trip to the temple and then go round in a convoy of trucks and song thaws to visit all their relies and, as you know, they have lots of relatives! I love the esteem which younger Thais show to older people. It is an all day-all night affair with lots of good food and drinking ending with a big party - really great craic. Only down side is the awful Issan music
Issan people are rightly renowned for their hospitality and they could not be friendlier to farang interlopers. Overall, a very enjoyable experience and you meet some great people.
LBloom