Any plans to make all champions F2P for a day?

I'm just curious, I was wondering if Riot will ever have a day where all champions will be F2P for at least 24 hours? As a veteran League player, this isn't an issue for me since I own all the champions except for like a couple, but I've notice all my new League friends are having trouble picking their next champion to learn. I'm always like... why don't try (champion)? Oh wait, nvm, it's not F2P and they don't have enough IP to buy the champion. Who knows how long before the rotation comes around for you to test that champion out. Having all champions F2P for 24 hours seems very beneficial and will keep a lot of new players onboard on what their next champion is to learn and to buy.