Brain farts aren't as productive as real ones.

haha, I'm proud of that title.

Anyway, I thought I'd post a link to an interesting article:
Mind-Reading Hat Could Prevent Brain Farts

The fact that there was observable abnormal brain activity was kind of a "duh" to me, but 30 seconds before? It must take people a while to start daydreaming (i.e. a very gradual transition).