It is a project about something you are currently interested in, or something you would like to learn about. There are several different intersting topics to choose one. If you would like to look for something on you own, try a search- middle school math webquest airplanes, or whatever you want to try to find. Just make sure they have enough information to do a project and an actually project that you produce.
Check out some of these:
Webquests
Webquests 1
Webquests 2
Webquests 3
Webquests 4
Webquests 5