I've hosted five times and co-hosted three times I believe, and each time it's been a great success. I've found the key is to get a good co-host(s) who will do the work of promoting, making good submissions for it, and making sure everyone's submissions get lots of love. And recruiting others to help promote is also key. And then actually do the work of promoting and participating myself lol It's baffling to me when people host a week, then don't even make any memes for it.