The outdoor 2nd Annual Earth Day Houston Festival, 5K & Green Expo starts with a 5K fun run at 8 a.m. and ends with the heart-thumping Latin rhythms of the Norma Zenteno band starting at 4:15 in the afternoon. In between, you can shop the farmers' market, peruse the AIA Gulf Coast Green Consumer Exhibition or just enjoy the sweet expanse of the Discovery Green lawns. 8 a.m. to 6 p.m. at Discovery Green, 1002 Avenida de las Americas. For information, visit www.earthdayhouston.org. Free.