Ban Wat Saen's longboats:
During ບຸນຫໍ່ເຂົ້າປະດັບດິນ Boun Hor Khao Padap Din (lit. festival wrap rice decorate earth) on the new moon day around late August/early September, Luang Prabang's annual longboat races (ຊວງເຣືອຍາວ suang heua yao) are held on the Nam Khan. People leave offerings of hor khao (little packages of rice wrapped up & steamed in banana leaves) around their homes & temple grounds for the spirits of the deceased, & 'boats' made from banana tree stems (looks like triangular, leaf-less & flower-less krathong) are floated on the river or left on the banks at various sites along the Nam Khong & Nam Khan where nagas are believed to live.
Each boat is believed to have two female khouan (spirits) called Nang Heua (lit. Miss/Lady boat) in it, so offerings have to be made before the boats can be used:
Interesting how the timing of this festival overlaps with 七月 (seventh month in the Chinese lunar calendar aka. 中元节 Hungry Ghosts festival), & shares the same elements of making food offerings to the spirits of deceased relatives...the Thai version described here shares even more similarities - the whole idea of the gates of hell being opened for the whole month for spirits of the dead to roam the mortal world & enjoy the food offerings & entertainment provided by the living to appease them. Not sure if it's only Luang Prabang town that holds boat races at this time of the year - Ban Xieng Ngeun further up the Nam Khan, Vientiane & elsewhere in northeast Thailand (e.g. Sakon Nakhon) have theirs in October during Boun Ok Phansa (end of Buddhist Lent/rains retreat) instead.
Wat Saen's alarm clock doubles up as a car shelter: