According to the USGS an earthquake measuring 6.3 hits northern Thailand at around 6pm Thai time. Epicentre is reportedly 9km south of Mae Lao (not sure where exactly that is) but I guess its near the mountainous regions of Chiangrai.
Pictures above shows some damage in Chiangrai and people evacuating buildings and the airport. Tremors were felt as far south as Bangkok so those of you doing some horizontal exercises an hour ago maybe you just weren't that great in bed?