To some people crosswords, sudoku and other puzzles are an intriguing mental exercise which keeps the brain active, and to others they are an appalling waste of time. There is certainly no lack of choice if you would like to access them on the internet :
http://www.crossword-puzzles.co.uk/ gives access to a very broad range of crosswords and other puzzles
http://www.puzzlechoice.com/pc/Crossword_Menx.html online crosswords and puzzles
http://www.puzzler.com/PuzzleCategory.aspx?NodeID=62 online crosswords and puzzles