Pasa Nua - it had several ancient alphabets, "Dhamma letters"!
The Saw and local music styles - see them at the Night Bazaar.
Fon Ngeu, Fon Kinaree and Fon Dap Shan sword dances: rare now.
Large funereal spirit houses - and fascinating spirit beliefs!
The Mengrai festival in January, and another Mengrai festival during Songkran in April.
Shan architecture and Shan Buddhas - see Wat Pa Sak, Chiang Saen, a beautiful example of Lanna architecture with many ornamental stucco reliefs, and Wat Tai Yai towards the south end of Chaing Rai City.
Amazing carved wood water dippers with moving parts, at Silver Birch on Pahonyothin by the turn-off to Jed Yot.
Huge, long Naga fish called 'payanak' and giant Pla Buek catfish, sometimes found near Chiang Kong - up to 2.5 meters and 300 kilos. They're caught late April to early June, especially at Ban Hat Klai.