Cosmeo: Discovery Ed's online homework help website. It costs, but you can get a 30 day free trial by registering.
Academic Earth: Watch lectures from today's top universities, including Yale, MIT, USC, and Harvard!
www.freerice.com- answer questions and this website donates 10 grains of rice per right answer to help end world hunger.
Time Toast- Create timelines online and share them on the web! Plus, it's totally free.
www.voicethread.com- A VoiceThread is a collaborative, multimedia slide show that holds media and allows people to navigate slides and leave comments in 5 ways - using voice (with a mic or telephone), text, audio file, or video (via a webcam). Share a VoiceThread with friends, students, and colleagues for them to record comments too.