All of my games are available to everyone for free.
However, if you enjoyed any of my games, a couple of bucks to cover website hosting costs and support my ongoing efforts would be gratefully appreciated. I think $2 per game enjoyed is a fair price. Thanks.
Dropbox (250MB Extra space)
Penzu (20% off yearly subscription)
Hole in the Wall Hosting ($10US per year for 300mb space, 30gb bandwidth)

Thanks Gui! much appreciated =) Also thanks for your tweet regarding my older games, don't worry I'll soon unleash them on the world.
I haven't ever studied psychological theory, though much of what I suggested is influenced by the books Getting Things Done (David R Allen) and No Plot, No Problem? (Chris Baty).