Gamasutra - Colt Whitaker's Blog - Gaming can Save a Life.
What was the cause of this result? The video game Re-Mission. Three hundred seventy five male and female participants in the study were each given a computer. The computer had one or two games on it depending upon whether participants were in the control or intervention group. For the control group, a Shuttle SB51G minicomputer contained a single commercial game for the participant to play, Indiana Jones and the Emperor’s Tomb. While the intervention group’s computers contained not only this commercial game, but also the intervention game Re-Mission.

CNET News - How to get DRM-free PC games: Just wait. Thanks Peter.
Spore by EA may be one of the most high profile examples of this practice. It shipped in late-2008 with SecuROM, a copy-protection technology that keeps people from installing the game on too many machines. At the time of launch, that number was limited to three, meaning a user who had purchased the software would have to keep track of where that software was installed and deactivate any old copies before installing it on new hardware. The move to include this, along with a check that would verify whether a copy was legitimate each time a user went online, resulted in plenty of negative press, bad user reviews, and piracy on an absolutely massive scale after hackers were able to bypass the security measures.