Well, I didn't get out to free RPG day.  I didn't know about this part, but it seems some publishers were also doing free downloads of certain products.  One of them in Green Ronin with their "True20" game system.  It seems they had some problems with too many people downloading so they decided to do a free download of different products most days this week.  Friday is the free download of True20.  It claims to be a simplified version of d20 and many people rave about it.

http://www.greenronin.com/

Oh that is so cool!  Karma for you!

Today's the day of the True20 free download.

Also, ENWorld has a list of Free RPGs on their front page:
http://enworld.org/