1. Tuesday Twilights at the Lady Bird Johnson Wildflower Center

5 to 8 p.m. Tuesdays through Oct. 29. $6-$12 admission. 4801 La Crosse Ave. wildflower.org

Enjoy your happy hours with fall flowers starting this week. The Lady Bird Johnson Wildflower Center has brought back its Tuesday Twilights series, during which it stays open late each week this autumn to offer live music, activities, signature cocktails from Tito's Handmade Vodka, garden tours and more. Don't miss checking out Fortlandia, a series of 10 custom-designed forts that will transport you to imaginary worlds. This week during Tuesday Twilights, Americana artist Jeff Plankenhorn provides the tunes.

2. H.W. Brands at BookPeople

7 p.m. Oct. 22. Free. 603 N. Lamar Blvd. 512-472-5050, bookpeople.com

From the New York Times bestselling author comes a sweeping history of the American West. In "Dreams of El Dorado," Brands tells the thrilling, panoramic story of the settling of this once-wild side of the country. He takes us from John Jacob Astor's fur trading outpost in Oregon to the Texas Revolution, from the California gold rush to the Oklahoma land rush. The Austin-based author has set a new standard for histories of the American West.

3. Astronomy on Tap

7:30 to 10:30 p.m. Oct. 22. Free. The North Door, 502 Brushy St. astronomyontap.org

This month's edition of the event dedicated to out-of-this-world topics is dedicated to the Frank N. Bash Symposium at the Department of Astronomy at UT that brings in outstanding young researchers from around the country. Among them is Evan Schneider, a NASA Hubble fellow from Princeton University who will talk about how video games have helped astronomers explore galaxies on supercomputers. There will also be telescopes, trivia and tacos.

 4. "Harry Potter Trivia" at Park at the Domain

8 to 10 p.m. Oct. 22. Free. 11601 Domain Dr., Suite 200. facebook.com/events/402952780659922

It's almost the time for a Death Day Party, Nearly Headless Nick-style. If you know what that is, you're probably ready to try your hand at Harry Potter trivia. The Park at the Domain will transform into the Great Hall of Hogwarts for this spooky night of trivia that will cover the original seven books and eight movies. There is space for 30 teams of up to six players each; have at least one of the players register the team no later than 6:30 p.m.