CoDependents Anonymous: 7:30 p.m. Thursdays, Presence/Holy Family Medical Center, 100 N. River Road, Des Plaines. Support group to learn how to have healthier relationships. Info: Marilyn, (847) 255-0134, or www.coda.org. Free.

Blood Drive: 8 a.m. to 12:30 p.m. Friday, Arlington Heights Senior Center, 1801 W. Central Road. Appointments, (847) 368-5760. Walk-ins welcome.

Opening Day: 2 p.m. Friday, Arlington International Racecourse, 2200 W. Euclid Ave. Free general admission for Opening Day; coupon for beer or soda and a hot dog for 50 cents to first 4,000 guests. Info: www.arlingtonpark.com.

Debunking Myths on Senior Healthcare Coverage: 4 p.m. Friday, Alcott Center, 530 Bernard Drive, Buffalo Grove. Experts on new guidelines of Medicare coverage, Medicaid and legal issues. Information on skilled nursing, assisted living, rehabilitation, home health care, hospice and palliative care, geriatric independent case management, patient advocacy, audiology. Q&A will follow. Registration required with Terri Ebner, (847) 850-2117. Free.

The Big Sit & International Migratory Bird Day: 5:30 a.m. Saturday, May 7, 2016, Crabtree Nature Center, 3 Stover Road, Barrington. Join Forest Preserve staff to observe as many bird species as possible when viewed from a fixed location within a 17-foot circle. You can experience the perils of migration in the Migration Obstacle Course. Free.

Roskam And Proft Speak at Republican Meeting: 8:30 a.m. Saturday, Palatine Township Republican Organization, 765 N. Quentin Road, Palatine. Congressman Peter Roskam and WLS radio personality Dan Proft. Free.

Northwest Suburban Genealogy Society Meeting: 9 a.m. Saturday, Arlington Heights Senior Center, 1801 W. Central Road. Reading Between the Lines of the City Directory presented by Teresa Steinkamp McMillin, certified genealogist. No fee or registration required; beginners welcome.