Tag along with the build up to Father's Day with a display about fatherhood. A slogan like BE A GREAT DAD or DADS ARE SPECIAL lends itself to a display of books on parenting, and biographies about fathers. Any book with the word "father" in it goes in the display.
A display called SCHOOL'S OUT ties in with summer activities for children. Put books about summer camp, outdoor activities, nature, kid's games, craft books, and traveling with children in this display.
There's a big readership for true crime books like Ann Rule writes. No fancy title is needed, just put a sign saying TRUE CRIME and fill it with books from the 364 section. There may be some biographies that will work for this too like Bonnie and Clyde or Al Capone.
Westerns are popular with older men in particular. Set up a display called the WILD, WILD WEST. Put in western fiction and also titles from the U.S. history section on cowtowns, Indians, and western life. Don't forget biographies of Jessie James, Wyatt Earp and other notables from that period. The nonfiction books will catch the attention of a younger audience.
Check in the reference section for Chase's Calendar of Events. Choose a few special days to use for quickie table-top displays. Make a single sheet sign from the computer giving the theme (National Yo-Yo Day or Paul Bunyan Day). Set out books relating to the topic. Most libraries won't have enough for a large display on these offbeat events, so keep it simple.