Surah al-Kahf on Friday
مَنْ قَرَأَ سُورَةَ الْكَهْفِ يَوْمَ الْجُمُعَةِ أَضَاءَ لَهُ مِنَ النُّورِ مَا بَيْنَ الْجُمُعَتَيْنِ
Man qara'a surata-l-kahfi yawma-l-jumu'ati ada'a lahu mina-n-nuri ma bayna-l-jumu'atayn.
"Whoever reads Surah al-Kahf on Friday will have a light shining for him from one Friday to the next."
Narrated by Abu Sa'id al-Khudri. Mustadrak al-Hakim 3392 (sahih according to al-Albani)
A short reflection
Friday starts at maghrib Thursday in the Islamic week. Read it once before bed Thursday night, or after Fajr Friday. The reward runs the whole week.