The answers to the clues below will have something in common:

1. Hopeful Mideast protest movement that began in 2010
2. Cash cache location, perhaps (with "bank")
3. Morally obliged
4. Emergency fix for a dead battery
5. Trusting act, often in a religious context
6. California city by Joshua Tree National Park

Answers:

1. Arab Spring
2. Bank vault
3. Duty-bound 
4. Jump start
5. Leap of faith
6. Twenty-nine Palms

Credits:
LA Times Crossword
February 29, 2016
C. C. Burnikel (#1-4)
LEAP DAY
 
NY Times Crossword
February 29, 2000
Peter Gordon (#5-6)