To cleanse or not to cleanse? That is the question.

I have been interested in health, nutrition, healthy lifestyles, and the like, for quite some time. I have tried various programs/lifestyle changes over the years in efforts to maintain a healthy weight (haven't we all?!). Several times I have come across the idea of doing a "cleanse". Most recently I was approached at a Bikram yoga studio to do a "cleanse" with 30 other individuals (the cleanse they were embarking on was a commercial cleanse, not something conjured up in a kitchen). This came at the same time as I received a call from a friend in Vancouver who was also doing a cleanse. She decided on "the Master Cleanse", which I had heard of, but always been weary of (also called "The Lemonade Diet").

So my question to others is -- have you ever "cleansed" or thought about doing a "cleanse"? Is it healthy to perform a "cleanse" of your internal organs? Thanks for your input!