Stopping Daylight Saving Time, or better yet, going to DST all year and skipping the few months of standard time.
what's a good idea to make a persuasive speech about? Like, for instance, 'should fast food be banned?' except not that of course. :) THANK YOU !
Paper or plastic? Pick a side.
How about Freedom of Speech? You could tackle the thorny side about the balance between freedom of speech and offensive speech.
How about "Is sodium really bad for you?" Which ties in to your original idea. It may surprise you.
I've been the captain of my High School's debating team for 2 years and counting, and one of the most interesting topics that aren't cliche include "Should schools ban uniform?", "Should citizens have the right to stay at home to defend their belongings during natural disasters?" You could also challenge yourself and write a persuasive speech on an uncommon point of view, like for example "Helmets shouldn't be compulsory" or "Recreational drugs should be legalised and regulated by the government"
Hope this helps :)