Star Trek franchise, have been very lenient when it comes to fan-made Trek movie projects. Basically if you are doing a Trek fan film just for fun and are not selling or profiting from it, they won't bother you with pesky copyright lawsuit. Now there's an effort to make a free fan-made adventure game series based on the original Trek TV show and there's even a playable demo you can check out now.
Titled simply Star Trek Adventures, the demo gives players a portion of the first game planned for the series, which is based on the original Trek TV episode Arena (the big Kirk vs Gorn fight). While the artwork needs a little work the idea of a point-and-click adventure game using the original series as its basis does have an appeal.
Download the Star Trek Adventures Year One demo at Big Download