I won't go into detail about the Landmark Forum, but you can find more here:
http://www.landmarkeducation.com/ I took several of their courses in 1996. I thoroughly benefited from the Forum and the Advanced Course. I did not like the others--at all.
I also do not like their teaching style, even though the benefits of the experience were there. I also do not like their high pressure marketing.
A couple of the main benefits for me: it completely got my past out of the way of my life; and I have very little emotional hook in what other people say or do.
It was incredibly freeing and I still enjoy the benefits.
PhotoReading, Spring Forest Qigong, and the Forum, I think, are a must for everyone.