Make the most out of short winter days and long winter nights
Is singling out Saturday for optional fasting allowed?
A hadeeth from Tirmidhi: (gist) Do not fast on Saturday except the what is fard. It is not haraam as such, but is disliked. The context is that Saturday is an auspicious day for the Jews.
Is singling out Friday for optional fast permissible?
Why is there a difference in the beginning and ending of Ramadan?
Basic guidelines on spiritual retreat.