This has always been one of my fave fantasies. The story The Decadent Underground is pretty exactly much how I'd like it to go (
www.dimensionsmagazine.com/forums/showthread.php) - being able to experience it with others who are also going through the same thing and enjoying it, that'd be great.
But there's so many other possibilities. I'd gladly spend a day as a 8000lb blob if there was someone (preferably female) there to look after me. Maybe tease me about how I've let myself go and casually mention that
maybe it won't wear off after 24 hours...
One that'd be really fun would be to go somewhere public at my present size (6'2", 270 pounds, so flabby rather than fat) then ducking out of sight for a few moments and putting on an extra 500 or so pounds before heading back out again and seeing if anyone notices. Kinda like Clark Kent jumping into a phone booth to turn into Superman, except it'd be me changing into a huger me.
Maybe a good place to try that would be a clothing store for really huge guys, and taking the biggest clothes they have into a changing room to try on. Then, once the curtain was drawn, taking the magic pill and starting to get fatter, bursting out of my old clothes rather than taking them off.
The noise might attract a sales assistant, the same one who gave me an odd look earlier when I grabbed those XXXXL pants. "Are you alright in there, sir?"
"Yeah, fine!" I call back.
Rrrip. Burst. Tear. Bulge. "Just a bit of a tight fit, y'know?"
Then I'd change into the new clothes, which would only just fit, and (after about ten minutes struggling) manage to squeeze myself out of the changing room to go pay for them. The looks of disbelief and confusion from people - some wondering how they could possibly have missed seeing the man-shaped whale come in the store, and the sales assistant who is too stunned by my change to do anything other than take my money - would be priceless.
And then it'd be lunches time.