Occasionally fans of a video game franchise will come together in their love of said franchise to create some sort of digital ode. This often comes in the form of a remake of a classic game, or an expanded universe-style spin-off. When this happens, one of two things usually happens. First option, the franchise owner discovers the project (usually after some sort of grassroots support from game news sites like this one) and immediately sends the lawyers in to shut it down. The first option is that the franchise simply ignores the project's existence, so long as there's no threat to an upcoming project.
Apparently Gearbox Studios has found a third option with an upcoming fan-made project called "Duke Nukem Next-Gen." The idea is to remake "Duke Nukem 3D," from the ground up, using the Unreal 3 engine. Gearbox currently owns the rights to "Duke Nukem" and would be in its legal right to shut the project down, but it seems the developer is actually encouraging the remake.
You can read the whole story in the Gearbox forums, but the crux of it is that the developer has granted the project (led by Frederik "Fresch" Schreiber) something that's called a personal non-commercial license. In layman's terms, it means that, so long as the project remains free and there's no intent to sell it in the future, Schreiber and his team is free to use the "Duke Nukem" name.
"Duke Nukem Next-Gen" is still super early in development, which just began a few weeks ago, but you can already see the fruits of their work in this test video. The project is likely a year or more away from hitting your hard-drive, but it's extremely encouraging to see Gearbox taking such a positive stance towards fan-made creations.
But, before you go off and design your very own "Duke Nukem" cooking sim, remember that you need to ask permission first.