General:
* Television is like a window to the world. (Emphasizes its ability to show us what's happening elsewhere)
* Television is like a giant storyteller, weaving tales both real and imagined. (Emphasizes its ability to entertain and inform)
* Television is like a hungry beast, constantly demanding our attention. (Emphasizes its addictive nature)
Specific:
* The news on television is like a storm, constantly throwing new information at us. (Emphasizes the fast-paced nature of news)
* Reality TV is like a car crash, you can't look away. (Emphasizes the captivating nature of reality TV, even if it's negative)
* A good documentary on television is like a journey of discovery, taking us to new places and revealing hidden truths. (Emphasizes the educational and enriching potential of documentaries)
The best simile will depend on the context and the specific point you want to make.