The July 8 demo is looking like it could be big. Originally scheduled to deliver a "constitution first" message, tomorrow's demo is now as much about demands for justice, outrage over recent acquittals of Mubarak-era ministers and the mistreatment of martyrs' families (with officers accused of shooting protesters let out on bail and their cases postponed recently).
The Muslim Brotherhood -- which has avoided recent protests, even going so far as to call protesters "traitors" -- has apparently had to fall in line with the popular mood (and its younger cadres' demands, most probably), and announced it will officially be participating. So will a lot of others, despite the tension and anxiety in the air these days. On twitter, at the fokakmenahlak ("split from your family") tag, young revolutionaries are sharing advice on how to get around over-protective parents and make it to Tahrir.