Indoor activities pique my interest more than outdoor hobbies.

I spend time doing activities such as solving puzzles and crosswords, watching cricket and playing chess. Many feel that solving puzzles is a strenuous job. I agree that it is a mental exercise but have personally experienced lower stress levels and better focus on work by solving puzzles. They help in improving memory and also attention to detail. Similar to the famous Sudoku, there are various Japanese puzzles like Kakuro, Hitori, Heyawake, Hanjie and Suriza. They are all distinct from one another and can keep you entertained for hours.

Slither Link is an excellent site for such puzzles.