There is plenty to do wants you are there:

Go Shopping.
Meet my extended family.
Have a Thai Style Barbecue.
Hire you a moped or super bike.
Get you a Super Soaker for Songkran.
A night out at the local clubs and bars.
Take part in a traditional Thai Wedding.
Introduce you to the Lanna Camp family.
Train for a day at the Kiete Busaba Camp.
Farewell meal at the River View Restaurant.
Ice Skating/Bowling/Swimming Lake Barbecue.

Visit to Doi Suthep & Doi Pui, where you will be able to take a look at their freak show of a museum.

But remember once there, things slow down....... abit!

For more info Chiang Mai