Seafair , the Seattle area's five-week summer festival, kicks off Saturday and continues through hydro-race weekend Aug. 5-7.

This weekend's Seafair highlights:

• Milk Carton Derby , Saturday: Nearly 100 creatively designed watercraft, floating on milk cartons, compete for speed and design in this annual event. Entertainment and prize giveaways on shore. Southwest portion of Green Lake (near Crewhouse), Seattle. 10 a.m.-3 p.m. Free to spectators.

• Classic Speedboat Show and Lake Union Wooden Boat Festival , Saturday-Monday: A celebration of classic boats and boating in the Puget Sound region, with more than 150 vintage craft on display. South Lake Union Park, adjacent to the Center for Wooden Boats, Seattle. 10 a.m.-6 p.m. daily. Free.

For more information on Seafair events: 206-728-0123 or www.seafair.com