This looks like it might well be worth a try. Upsides – simplicity, low cost. Potential downsides – not going to work well to develop ‘To Do’ lists for specific environments.
[youtube=http://www.youtube.com/watch?v=qF1ngJAyD_s&eurl=http://www.markforster.net/autofocus-system/&feature=player_embedded]
Video is about 9 minutes and needs sound.
Or you can just check out the website – with some really simple getting started instructions here.