We have so many t-shirts hanging around it's unreal.
So I commandeered one of my daughter's and set to work with the scissors (as you do). I cut off three bands of fabric from the bottom, cut off the neckband and shaped the top into a bolero top. With the bands of fabric I joined them together, made a ruffle and then stitched the ruffle onto the top.
She wears it over her princess dress <grin>.