First off, you should visit Wikipedia today. Search for something. Anything. You'll see that the whole English version of Wikipedia is being blacked-out in response to the SOPA act currently before Congress. The SOPA act is a piece of legislation that could have potentially far-reaching consequences regarding how the whole internet functions, so if you like the internet the way it is (extremely free, extremely awesome), consider writing to your congressperson and telling them so.
Next up, you should go to Underwater Sculptures and see some of the really cool artwork made by UK artist Jason deCaires Taylor. His work is a win-win-win: he is calling attention to the devastation wrought upon coral reefs by careless tourists, while simultaneously providing an awesome alternative for those tourists to explore AND giving animals a great new habitat. Oh and the sculptures themeslves are gorgeous, especially after the sea has had a chance to work its magic on them for a while. Here's a slice: