limiting query with created_at?

I have no idea why this isn't working but maybe a new set of eyes can
help. I want to only collect posts from yesterday:

   Post.find( :all,
              :conditions => "posts.created_at > #{(}",
              :order => "posts.created_at DESC",
              :include => :person)

Let Rails convert the time into the format your database expects...

:conditions => ["posts.created_at > ?",]

Otherwise you're going to need to format that time so your database
understands it.