Google Wave (currently in preview) is a new online collaboration tool created by Google. It provides the opportunity for asynchronous and synchronous communication among users. Waves allow participants to share resources, images, videos, documents, etc in order to discuss, collaborate, etc. It's a wonderful tool and my guess is that it will only become more powerful when it is open to all and a little more polished. Even in it's current state, it's quite robiust.
Scratchpads are an easy to use, social networking application that enable communities of researchers to manage, share and publish taxonomic data online. Sites are hosted at the Natural History Museum London, and offered free to any scientist that completes an online registration form. Scratchpad users include societies, journals, scientists, students and amateurs. Any group with an interest in natural history is eligible for a site and you do not have to have an academic affiliation, or any professional qualification. All you need is a little time, some information you would like to share, and a little experience using the web. You don't need to even be a member of a group, although the best sites are usually those developed by a community who make regular contributions.
Google Voice is another Google product currently in preview. Google Voice might just revolutionize phone and voice mail. With google voice, you get a phone number that you could essentially use as your only phone number in the (near) future. Essentially, you can forward calls from the google voice number to any number you like and even change what number it is forwarded to based on the time. In other words, you can forward calls during the day to your work phone, in the afternoon to your cell phone, and in the evening to your home phone. You can even have the phone ring on all these numbers at all times if you like. Furthermore, you can set different numbers to ring to a different phone (i.e. friends always go to cell phone, work contacts always go to the work phone, etc.). As if that weren't enough...you can even set custom outgoing messages based on who (or what group) is calling. And there's more!!! Voicemails that come in are transcribed as text and can be delivered via email or sms.
30 Boxes is an online calendar that works great for students due to its simplicity and sharing options. It features RSS subscription to automatically populate the calendar with feed items. Users can even access their calendars on the go.