Examples
You can go to http://www.youtube.com and search for MEC101 Stony Brook and you will find hundreds of video demos of the robots that MEC101 students have created in the past. Take a look at them to gain some inspiration, but definitely not copy them. Use your own imagination and creativity.
Also, you can look at the pictures of what students have created in the past in this class. Click on Demo Pictures
Please take a look at the example projects found elsewhere to get an idea for what are the possibilities. This will also help you decide on your own project. However, not all of them qualify to be a valid project for our class specially this year since the theme is different.
There are a lot of interesting robots and mechanisms on display at youtube.com.
Search for robots, mechanisms, kinematics as key words. Complexity could be widely varying. You should pick something that provides the right balance.