How about the 6th of each month? It'd definitely be easy to remember that one.
Oh, yes, that's a good idea. The 6th of every month could be the No. 6 Day.
The No. 6 Week was/is a great idea... it was necessary to breathe new life into our fandom. A lot of people seem to appreciate it. And the various topics will help to create a lot of different No. 6 themed artworks [hopefully] in a short time. Even if some works are quick and rushed doesn't mean that they're bad. Sometimes... a quick sketch can be more interesting than a 36hours without sleep artwork. XD
But well, of course I agree with you, that's why I started this poll. I have to admit, I wanted to vote for the No. 6 Weekend, but I totally like your idea... that's why I vote for the No. 6 Day. I mean one day is enough... and even if you worked on something but failed to post it on that day doesn't mean you can't post it a few days later. ^^ It's not obligatory.