Coastal Cleanup Day
Ocean Conservancy spearheads the annual event, with this being the 25th year. You can find an event near you by searching via this map.
In California, the event has earned honors from the Guinness Book of World Records as "the largest garbage collection" (1993). Last year, fourth-graders in New York City gathered debris, catalogued it and shared their thoughts; as Oliver said, "Birds are lovely, and die from us. When they see a lot of trash, they don't think once, they just eat. Then are poisoned."