I use pen and paper for that. One reason is that having to stop and make a written note raises the costs of changing activities, which can help keep me on trac

I use pen and paper for that. One reason is that having to stop and make a written note raises the costs of changing activities, which can help keep me on track. Naturally, this won't help much if you can't remember (or be bothered) to actually do that, but it is an alternative; actually, I found the notebook lying off to the side of my desk to be a decent reminder in itself to make notes.