you can make an electric piano guitar or hack something
Look around your home, not the internet. L
what would you be intrested in? Wood? Electronics? Metal Working?
Instructables if full with ideas of things to do. You just need to browse through.
Start here, and then use the menus on the left of the screen to narrow your search until something catches your eye. If you feel like it, there is a link just above the thumbnails called "random" - try clicking it a few times.