Related Clues:

• Hint
• Prompt
• Nudge
• Memento
• ''My Very Easy Method: Just Set Up Nine Planets,'' e.g.
• Souvenir, e.g.
• Memory jogger
• Note on the fridge, maybe
• String around your finger
• String around your finger, e.g.
• Souvenir
• Study aid
• Post-it Note, perhaps
• Note to self
• Memory aid