Putting on my Tim Stone hat, I noticed that strategy-specialists Matrix games have celebrated the US tax day by giving away the full version of their War Engine game. That's very different to how RPS celebrates its tax day - that is, with a cheery bout of tax evasion. Don't be confused by the fantasy screenshot - the War Engine is a general purpose wargame which allows you to construct your own turn-based military fisticuffs. There's eight (Count 'em!) campaigns included, though one appears to be a pure training one. They vary from fantasy turn-isms to Space-based turn-isms to Laser-squad-esque turn-isms to Paintball-turn-isms to... well, people who are into turn-isms are going to be as happy as when the international sanctions on the trade of turn-isms from turndondonia was lifted. This post is rapidly making no sense whatsoever.
The full download is just over six and a half peggles, and is available here. And after having a crack, I'm tempted to challenge you lot to make your own RPS War Engine campaign.