More than 4,000 kids ages 5-14 from Washington, Maryland and Virginia spent the day Thursday exercising their bodies and their minds as part of the YMCA's  Thingamajig Invention Convention.

More than 50 workshops led by the Y and other organizations and businesses were planned, with an emphasis on inventions using recyclable materials.

A 9-year-old camper told a Y staffer that “it’s the best thing in my life next to Christmas,” according to the organization.

More than 400 volunteers were participating and more than 20 organizations hosted workshops, including AOPA, Tuskegee Airmen, FIRST, National Science Foundation, SCRAP DC and the US Patent & Trade Office.

AOL, Patch's parent company, participated, and Patch editors, including Katie Griffith, Ryan McDermott, Sean Sedam and Tiffany Arnold, talked to kids about online journalism and Internet safety.

The event at the Show Place Arena, 14900 Pennsylvania Avenue, in Upper Marlboro ends at 3 p.m. and is open to the public.