This general question in Stack Overflow links here and the first answer, that Microsoft couldn't, is the right answer for your question. Qwerty above suggests Spore. Brant Bobby gives a rational and detailed answer to your very question - like many of the answers here, ideal to convince people who think like us of the utter futility of DRM, copy protection, etc.
So - why am I still here? It's because you asked the question wrong - and I know what you should know too. You probably aren't trying to convince someone that DRM cannot work at preventing copies. Instead you're probably trying to convince them that DRM isn't worth it, which is much more difficult, and the Spore and Microsoft examples aren't useful there. What you need are facts.
Here's a fact that makes managers loose sleep at night. Approximately 90%. That's how many of your users might be pirating your goods. 90%. Here's where things go wrong - the manager thinks - if we could convert those 90% pirates into sales, why, our money problems would be solved! If we could only convert even a fraction of them! And so, the decision is made - DRM will increase conversions and reduce piracy some, so they want it. We need to rain on their parade with another number. 0.1%. That's 1 in every 1000, and is roughly how many of those pirates will convert if you break their free distribution of your data. So, let's do the math - 1000 paying users + 9000 pirates * 1 / 1000 = 1009 paying users... Let's ask yourself - are those nine sales justifying the cost of the DRM - including the loss of network externalities (make sure to use that phrase - if they were trained in business school, it's their Power Law).
If your data that needs to be protected is selling for enough per copy, those 9 customers might pay enough to make it worth it. Or, if you have 1,000,000 paying customers, you'd earn 9,000 sales, certainly worth it even at $5 per copy, right? Let's drop the other shoe and provide another case study: 2D Boy's World of Goo. They make the blatant claim to having no DRM. And their piracy rate was a mere... 90%. That's about the same piracy rate as Reflexive - who were releasing from the start with DRM. Actually it's possibly lower, down to 82%. No statistical difference. They didn't follow the industry accepted practices, but it still worked just the same.
The time comes then to make a decision - to accept DRM and the tricky problems it brings, assuming and hoping that the conversions come in to justify the price - or alternatively to take the plunge and assume that your customers aren't different from those of Reflexive and 2D Boy, and maybe save the full cost of DRM to use on the next big thing. With what you know now, I'd pick no DRM - but I could be wrong in doing so.