The Hopkinton Marathon Committee is sponsoring a free 100-yard dash for children ages 5-12 on Saturday, April 18 (two days before the Boston Marathon) at 2 p.m. at the Town Common. Participants will receive a T-shirt, race bib and finisher’s medal. Advance registration is required by April 10, and the event is limited to the first 200 to register. For more information, visit hopkintonmarathoncommitteema.org.