The Sweater Set perfoms at Ukulele Festival this weekend. (Rachel Fus) Our picks for the best free events this weekend, including a festival dedicated to the Ukulele and another classic film starring Humphrey Bogart.

MONDAY

More Bogie

The National Theatre continues its Humphrey Bogart summer series with the Howard Hawks-directed film noir classic “The Big Sleep,” starring Bogart as a private detective who gets tangled in murder, blackmail and love after being hired by a wealthy family.

TUESDAY

Jobs panel

It’s been everywhere in the news: the ever-changing job market. Former members of Congress take part in a panel looking at how the economic problems facing the United States compare with past recessions and which historical ideas have worked or failed.

WEDNESDAY

Incwell

The local rapper, who blends hip-hop with traditional rock-and-roll and other sounds, performs a free outdoor concert at Strathmore.

THURSDAY

‘Dancing in the Rays of the Antarctic Sun’

Filmmakers Joy West and Laura Ward Holliday screen their movie, which combines 14 poetic works with sweeping shots of Antarctica’s icy, pristine landscape.

FRIDAY

Mars Day

The National Air and Space Museum celebrates the Red Planet with interactive discussions with scientists involved in Mars research, a 3-D display of the planet’s surface, an exhibit of a meteorite found on the planet and hands-on educational activities.

SATURDAY

Ukulele festival

It’s an event for all things ukulele. Local players perform throughout the day, including Baltimore-based Victoria Vox and multi-instrumental duo the Sweater Set. Attendees also can take part in public jam sessions and visit arts and crafts vendors.

SUNDAY

NSO Summer Music Institute Orchestra

Musicians ages 14 to 21, participants in a four-week program with master classes and coaching by National Symphony Orchestra performers, will present a program featuring works by Rimsky-Korsakov and Sibelius in the Kennedy Center Concert Hall.