Try cheese, a feature-rich Ubuntu equivelent to Mandycam complete with effects, support for taking videos and pictures, and a simplistic user interface. You can install it from the Ubuntu Software Center. To do so, follow these steps: Click the bag icon on the left side of the screen that looks like this:
In the search box in the upper right hand corner, type in cheese. Click on the result of "Cheese Webcam Booth" and click install. Enter your password to confirm that you want to install cheese, than press enter. Wait until the installation has finished, and Ta Da! Your'e done.