Waipahu Town Center will host a Happenin' Halloween day of activities from 11 a.m. to 1 p.m. Saturday.

The Blood Bank of Hawaii will host a blood drive in New Hope Leeward's foyer area from 10 a.m. to 2 p.m. Call 845-9966 for details.

Additionally, there will be a costume contest for all ages from 11 a.m. A grand prize valued at more than $500 consisting of donations from center merchants will be given to the "best of show." There will also be prizes given for the scariest, funniest and most creative costumes. Pick up registration numbers under the big white tent between 10:30 and 11 a.m.

Jolly Josh Balloon Arts will also be on hand.