It worked for me when I wrote GCC-CIL, and that was one of my most productive periods ever. I worked a 40 hour/wk job at a research lab and hacked on GCC-CIL on evenings and weekends, progressing so quickly that it freaked out my mentor. But this data point really means nothing... it's probably just an indication that you have to be either drugged or insane to hack GCC's internals without vomiting.

Overall, I don't recommend it. Do it every once in a while and you might have some cool ideas, but I bet you'll spend most of your time giggling and watching The Simpsons. I have not experimentally confirmed this, but apparently proper use of hallucinogens is the way to go for broadening perspective and etc. I'm personally interested in learning meditation techniques and seeing what sorts of effects that can have on the mind.