Jing

I use this free screen capture tool almost every day.
Check out this screencast I made with Jing (you'll want your speakers/headphones on).

Dropbox

Click on the title of this post to go to the website. Watch their two minute video. Download and install it. You'll never be the same. It's synced, online storage. For example, I create a Word doc on my desktop at home. I drag it to the Dropbox folder on my desktop. When I get to school, the document is already on my laptop. You can sync any number of computers, share files (publically or privately) and your stuff is always available online as well (in the case where you find yourself on someone else's computer). Do yourself a favor, just watch the video on their website.

Readability

This browser app is genius. It turns this super annoying, busy page (above), into the large font, clean page (below). In short, it takes out all the web noise by just giving you the content related to what you are reading/viewing and filters out all the rest. Click on the title of this post and follow the two easy steps to install it in your browser.
It's so simple to use. Once it's installed in your browser, just click on it when you're on any website (except home pages) and it'll automatically make it "readable."

Watch a short screencast about it here.