A woggle donut will hold your curtain
The pool noodle inventor probably never thought his invention could do this: someone used a piece of noodle to hold their curtains. Once again: wrapping the foam would make it look so much prettier. Still, it is a bright idea.
Cut a piece of foam in the shape of a donut. Then, open it from one side, and it will look like Pac-man. It is easier and quicker than grabbing the curtains with a ribbon (which would look much prettier but might be more expensive).