1. Oktoberfest: The second week of Oktoberfest under a big top at Tampa Bay Downs brings an adorable contest of corgi racing to the racetrack. The festival also features a carnival, arts and crafts, German food, drinks, music, dancing and contests for log sawing, stein holding and keg hurling. $5, 12 and younger/military free. The corgi race starts at 1 p.m. Saturday. 5-11 p.m. Friday, 11 a.m.-11 p.m. Saturday. 11225 Race Track Road, Tampa. (813) 855-4233.
2. Riverwalk Trick or Treat and Movie: Costumed kids and their families can go trick-or-treating for candy along Tampa’s Riverwalk from 4 to 7 p.m. Saturday. Stick around afterward at Water Works Park for a free screening of Tim Burton’s Corpse Bride. Free. 7 p.m. 1710 N Highland Ave., Tampa.
3. Opera Tampa: In a concert called The Witching Hour, something wicked this way comes when the Opera Tampa singers unleash superbly concocted witchy tunes. Free. 7-8:15 p.m. Friday on the Riverwalk stage next to the David A. Straz Jr. Center for the Performing Arts, 1010 N MacInnes Place, Tampa.
4. Henry Plant’s 200th Birthday: Tampa’s Plant Museum is celebrating with a lecture, book signing and birthday cake to honor the man who is the reason the first steam engine arrived in Tampa in 1884. Visitors are invited to explore a special exhibit called “Henry Plant: He’s More Important Than You Thought.” In a special Upstairs Downstairs performance, an actor will bring Henry Plant to life at the turn-of–the-century Tampa Bay Hotel. Then there will be a talk by Canter Brown Jr., Florida historian and author of the new biography Henry Bradley Plant: Gilded Age Dreams for Florida and a New South. Free. 2 p.m. Sunday. Henry B. Plant Museum, 401 W Kennedy Blvd., Tampa. (813) 254-1891.
5. Hope Spot Celebration: Renowned scientist Sylvia A. Earle will be in her hometown of Dunedin to recognize it as a newly designated Florida Gulf Coast Hope Spot. Those are special places critical to the health of the ocean. Earle is a world-renowned oceanographer and founder of Mission Blue. In 1979, she set a record for the deepest dive without a tether. She was the first woman to become the chief scientist at the U.S. National Oceanic and Atmospheric Administration, and Time magazine called her a “Hero for the Plane.” There will be a special ceremony at 1 p.m. Saturday, followed by fun scientific activities for families. Free. Pioneer Park, Main Street and Douglas Avenue, Dunedin.