From the page you're linking to:

Hello! Before you can sign in and download Joost, you need an invitation from another user.

oh, I made a mistake. It seems its cookie-persistant. sorry everyone..

to correct this, i can give invites to anyone who wants,

Could you email one to me?

My address is denis.papathanasiou (at-sign) gmail.com

I would like one please. Thanks,

Bit Bitdiddle

bitdiddle@member.fsf.org

Could I grab an invite? ryan@junee.org

Cheers, R

I'd appreciate one, too:

fedorov@rutgers.edu

invite please :-)