Atttended a Tiago Alves (2005 Mundials runnerup, 2006 Pan-Ams Champion are his most recent notable titles) seminar today and it was great. I really don't even like seminars that much to be honest with you... its usually just too many moves and not enough drilling of them to really remember anything anyway. However, Tiago gave us a lot of time to drill the techniques he instructed, and he still managaed to cover a lot of different aspects of his game in the 3 hour seminar.
Most importantly for me was that even though his english was not that great, I still picked up some GREAT details that will not only help in the techniques he taught today, but also with techniques that are already a part of my game. It was a really great seminar.
I just heard he is doing another one in Las Vegas on September 2nd at Mica's Machado BJJ Academy. Their web site is www.bjjlasvegas.com, I don't think info is up on there yet, but its $50 and is at 12pm. It is definitely a good seminar so if you're in Vegas you should try to check it out. Contact someone at Mica's academy for more info.