Related Clues:

• Grays
• The Muses' domain
• Quite some time
• 'Forever'
• Seeming eternity
• A lot of time
• Song and dance, e.g.
• Many years
• These may be fine
• Kennedy Center focus
• Long, long time
• See 57-Across
• Quite a while
• Lincoln Center subject
• Fine or liberal follower