By offering Napoleon: Total War for two bucks! Er, 200 pence. In any event, if you head over to the Humble Store between now and June 22nd, you'll find this awesome strategy title on sale for $2.00. That's a steal.
The other cool thing is that they're working with "Waterloo 200," the official body supporting the commemoration of the battle’s bicentenary, and 50% of proceeds will be donated to their chosen charity, Walking with the Wounded, which provides re-education and re-training for wounded service men and women for new careers outside of the military.
So head on over and check it out!