Games:

• SudokuLink opens in a new window and more SudokuLink opens in a new window (Yahoo)
• FreeCellLink opens in a new window
• CrosswordsLink opens in a new window (Guardian)
  
• KreuzworträtselLink opens in a new window (Die Zeit)
  
• Crack ItLink opens in a new window
  
• Bubble ShooterLink opens in a new window
  
• Online Logic GamesLink opens in a new window
  
• Store web gamesLink opens in a new window

Fun&Info Videos

• TED-EdLink opens in a new window
  
• MinuteEarthLink opens in a new window
• MinutePhysicsLink opens in a new window
• KurzgesagtLink opens in a new window ("in a nutshell")

Stars:

• Astronomy Picture of the DayLink opens in a new window

• HubbleSite NewsCenterLink opens in a new window

• Sky MapLink opens in a new window 
• AstroBiology NewsletterLink opens in a new window

Fun & Nonsense:

• XKCDLink opens in a new window
• 3D FractalsLink opens in a new window
  

• WordleLink opens in a new window

Other:

• Onlinestreet: Ausgewählte Webseiten, Erfahrungsberichte & Nachschlagewerk
• Less WrongLink opens in a new window - a community blog devoted to refining the art of human rationality
• EdgeLink opens in a new window: Conversations on the edge of human knowledge
• wiseGEEKLink opens in a new window: clear answers for common questions
• MemriseLink opens in a new window
• LifehackerLink opens in a new window
• Wonder Ho ToLink opens in a new window
• David Colquhoun's Improbable ScienceLink opens in a new window
• Number WatchLink opens in a new window

• PhotographyLink opens in a new window

• Amnesty InternationalLink opens in a new window
• LACUNALink opens in a new window
• AVEN - Asexual Visibility and Education NetworkLink opens in a new window
• MiDoMiLink opens in a new window (Search for Music Using Your Voice)