I got it too. Everyone change your passwords! The server has definitely been hacked, and this does not appear to be the first time...
I did a search on the server's ip address and found that it was hacked most recently in June 2015 or earlier. That hack is still there! Open link at your own risk: http://dnd.opengameart.org/memberal.php
I searched Duck Duck Go for the server's IP address. The first real hit was this: http://www.leetsmirror.com/ip_199.180.155.30.html
It says that hacker Memberal_Force hit the server back in June. I don't know if it is the same thing that caused today's email spam though.
Now that opengameart.org is back online, it looks like that Memberal_Force thing been cleaned up at least.
I got it too. Everyone change your passwords! The server has definitely been hacked, and this does not appear to be the first time...
I did a search on the server's ip address and found that it was hacked most recently in June 2015 or earlier. That hack is still there! Open link at your own risk: http://dnd.opengameart.org/memberal.php