There are many hundreds of online resources that can help you build up your brainpower! Below are a few of the most comprehensive and useful, grouped into different categories (for instance, memory strengthening or vocabulary building). Category Resource Vocabulary and word-building The Word Search Washington Post Daily Crossword Foreign languages Memrise Duolingo Brain teasers and logic puzzles Riddles.com Web Sudoku Luminosity Brain Training Trivia Sporcle