Indie Bookstore Day is set for April 28, and throughout the nation, indie booksellers are preparing for the fourth annual national outpouring of support for books, writers, and community by scheduling author events and activities as well as stocking up on exclusive merchandise. This year, 507 indies in 48 states (minus Hawaii and Arkansas) are taking part in Independent Bookstore Day, up more than 5% from last year’s 480 participating bookstores. This year’s IBD ambassador is novelist Celeste Ng.

“It just keeps growing and it’s really taken on the feeling of a holiday among booksellers and book buyers,” IBD program director Samantha Schoech said, noting that IBD is commemorating Harry Potter’s 20th anniversary this year with a special item relating to the beloved boy wizard. It is among the 15 IBD exclusive items that are available only in participating IBD stores and not online. The exact nature of the Harry Potter item will be announced closer to April 28.

“This is generating even more excitement for IBD this year,” Schoech said, “After all, there are legions of Harry Potter fans.”

Several bookstores are turning their stores into performance spaces: singer-songwriter Robert Hunter is already getting indies stoked for IBD by having kicked off this past weekend the national tour for his debut novel, Relapse: A Love Story (Beaver’s Pond Press). Hunter is signing books and performing at a different indie bookstore (or local pub) in a different city each evening leading up to April 28. Toadstool Books in Keene, N.H., will offer an IBD musical performances by an a cappella group from Keene State College called Chock Full O’ Notes. A Harry Potter-themed band will entertain at Novel Neighbor in Webster Groves, Mo., while, in nearby St. Louis, Left Bank Books will kick off IBD with literary pancakes and, that evening, wind things down with a literary dance party. In Chapel Hill, N.C., Flyleaf Books is going to celebrate IBD with refreshments throughout the day, followed in the evening with indie rock icon and dBs founder Chris Stamey reading from his new memoir, A Spy in the House of Loud (University of Texas Press) followed by an in-store concert. “So indie bookstore, indie rockstar, indie publisher,” pointed out owner Jamie Fiocco.

Some indies are taking the opportunity to draw attention to important causes besides literacy. As part of its Read Write Resist partnership with Arizona’s ACLU, Changing Hands Bookstore in Phoenix and Tempe, Ariz. has invited representatives from regional branches of such groups as the ACLU, Moms Demand Action, International Rescue Committee, Living United for Change, and the Council on American-Islamic Relations into both outlets that day to educate customers of their work.

It’s all about books and environmental sustainability for Flintridge Bookstore & Coffeehouse in the Los Angeles metro area. For adults, Michael Peevey and Diane Wittenberg will read from their self-published book, California Goes Green: A Roadmap to Climate Leadership, while for children, Bethany Barton will read from her picture book, Give Bees a Chance (Viking). Later in the day, poet Kim Dower will emcee an open mike. The Raven Bookstore in Lawrence, Kan. will donate 10% of the store’s profits on IBD to Every Town for Gun Safety.

Each year, more and more indies are banding together to entice booklovers into making a full day of it with some literary road tripping. Indies in the San Francisco Bay Area, San Diego, Seattle, Twin Cities, all of the Vermont indies, are among the regions partnering to offer passport programs with prizes and/or discounts for participants in there area. In Boston, booklovers can enter into a raffle for two baskets of books and swag at each of 12 participating bookstores: one basket at each store will contain items from that indie, and another will contain items from local publishers. Also, those visiting at least eight participating bookstores on what is being billed as Metro Boston Bookstore Day will receive a hand-selected stack of up-coming and prized ARCs.

In Chicagoland, 27 indie bookstores throughout the city and several inner-ring suburbs are gearing up for the second annual #MyChicagoBookstore Challenge. Customers making a $25 purchase at the first store they visit will receive a passport and a stamp. They don’t have to make any additional purchases at other stores they visit to get stamps. Anyone with a passport stamped at 10 stores will receive a 10% discount at all the participating stores for the next year. Anyone with stamps from 15 or more stores will receive a 15% discount. New this year is a social media component: a Google map directing customers to participating stores.

In another new initiative, the Midwest Independent Booksellers Association rolled out its Midwest Indie Bookstore roadmap, created by illustrator Kevin Cannon, who has made the Twin Cities IBD illustrated bookstore maps for the past couple of years. The 22” x 28” map (which can be folded into a 4.4” x 7” packet) features custom-made illustrations of member stores, as well as generic illustrations of non-member bookstores. Only bricks-and-mortar stores that sell frontlist titles and are located in MIBA’s 10-state region are included on the map, which will be updated every year for IBD. The map, according to MIBA assistant director Robert Martin, “will not be to scale, but will feature basic landmarks and highway systems for a fun and user-friendly orientation.”