I don't want to get any backs up, but what TemplatePlazza are doing this month has simply not been done before with a Joomla theme. The technology is there and it's not the most difficult thing, but it's now down and expect others to follow.
It's actually quite funky and like I said, unique to Joomla, or is far as I know anyway, and I play with Joomla every day, but with it carries a lot of work. You can't just install this - you've really got to put the work in and while my nature is that of a lazy git, this is something that would make me put in the effort again, much like something else I'm going to post about later today.
I could talk about this one all day and list several reasons why it is unique, but I'll leave that to you to see. Click here and visit TemplatePlazza for a demo.