Tab for a Cause is a website/browser extension that raises money for charity as you use the internet. Every time you open a new tab, you will be redirected to a page that shows 2 ads in the corner. You also gain a heart every time you open a new tab, which you can use to pick a charity you want to donate to. You can customize the page so it displays things like bookmarks or a clock.
If you already use it, what level are you on? I'm on level 16 right now. I mainly donate to Room to Read.