Dark periods for advertisers

• Casual evenings
• Dark times in the ad biz
• Evenings in the classifieds
• Evenings, casually
• Evenings, on some signs
• Post-dusk periods, in ad copy
• Times in ads
• Evenings, in ads
• Show times, informally

Wiktionary Word definitions in Wiktionary
n. (plural of nite English)