I use Firefox. I'm in the process of adding extensions to a new profile, and found Hungersitefox. That's a mouthful, but it's an extension I just added. It puts a link in the status bar each day. When you double-click the link, it opens with the Hunger Site, Breast Cancer, Literacy, Rainforest, and animal help sites, where a single click helps fund each of these charities. This is definitely something I will make a part of my daily browsing routine. You can find the extension on the Mozilla Update site, or at on this page, where there is also a bookmarklet version available.