“anybody have ideas on collecting things you think of in the shower?”
Although I’m not a GTD Connect member, I do have an RSS feed for David Allen Company Updates. I recently saw an item in the feed asking “anybody have ideas on collecting things you think of in the shower?”.
Personally I keep a small dry erase board, about 1’ square, within arm’s reach of the shower door. Mine has held up well and you can even get one at dollar store.
Although I haven’t tried it, another option is to seal a smartphone in a zip-lock bag.