Some of the members of Bullshido will be hosting a Throwdown at Fighthouse in NYC. The same place where the Daido Juku seminar was hosted. Basically it's open mat sparring with the benefit that people from multiple styles will be there to participate. So if you've never grappled, or sparred with head shots it's definitely a benefit because you can spar outside of your normal rulesets. It's open to people who are beginners or experienced fighters. It's up to you and your sparring partner as to how hard you want to go, and rules eg. MMA style but no knees or elbows to the head, San Shou, grappling whatever. But I do definitely suggest you specify any rules before you start sparring and bring whatever equipment you have, but especially a mouthpiece and a cup. Also you must be 18 or older because you have to sign a waiver to participate.
http://www.fighthouse.com
http://www.bullshido.net/forums/showthread.php?t=49054