Practically every open stretch of land becomes a concert ground in April. The Louisiana Philharmonic Orchestra (www.lpomusic.com) presents Singing in the Oaks on the Woldenberg/Goldring Great Lawn in City Park at 6:30 p.m. Wednesday. Expect everything from H.M.S. Pinafore to polka to pieces by Tchaikovsky and Wagner. Rain date is Thursday. Free admission.