A good place to start is:
http://www.censusonline.net/multi2004/indexmulti.html
Then click on "Sample from the Interim Population". Up pops a whole heap of information, but if you click on the link to "40 student designed questions", that will show you 40 questions that heaps of people have answered in an online survey. It will at least give you some sort of ideas about some questions to ask. Question 40 actually contains five separate questions in itself.
Actually, the six dot points under the red writing on this page give some really good steps in designing a survey, so have a browse through those.
You might be interested in comparing males and females in your class to amount of TV watched or amount of time spent smoking or other such stuff.
If you click on "Sampler", you can get a sample of actual answers. It will download as a CSV file, but you can then look at it by opening Excel (or some spreadsheet application) and opening the file from there, or by dragging the icon onto the icon for the application.
Anyway, it's a starting point.
Hope this helps.