Volunteers needed for Tinman

The Tinman Triathlon needs volunteers for various jobs — including course marshals and set-up and breakdown crews.

The July 29 event needs 24 marshals for the run course and 30 for the bike-transition corral. Set up duties are from 8:30 a.m. until 12:30 p.m. July 28, and breakdown duties are from 10 a.m. until 2 p.m. July 29.

For information, contact Joan Davis at 535-9070 or email jrdva4vp@hotmail.com.

» tinmanhawaii.com

Olympic Day at BMX track

In conjunction with the global Olympic Day celebration, Island BMX is hosting a free Olympic Day/Family Fun Day Saturday at the Sandbox Track on Sand Island.

The track opens at noon with registration starting at 3 p.m. and racing at 4:30 p.m. The event also includes a chili cook-off at 4 p.m., with samples sold for $2.

BMX is one of the newest Olympic sports, making its second appearance at next month’s London Games.

» islandbmx.org

Roller derby doubleheader Saturday

Pacific Roller Derby hosts California’s V Town Derby Dames in a doubleheader Saturday at Palama Settlement Gym.

The 6:30 p.m. opener features the Hulagans, PRD’s all-star travel team against the Dames from Visalia, Calif. The second bout has the B teams from both leagues — Bizz-nass vs. Darlings — at 8 p.m.

Admission is $10, $7 for students with ID. There is no charge for children 12 and under.

» pacificrollerderby.com