Each year the Colorado Division of Wildlife (DOW) gathers along several rivers throughout the state to collect eggs from spawning Kokanee Salmon. The eggs collected from these fish are then used by the DOW to raise a new generation of Salmon. Once the Salmon are a little older they are reintroduced to lakes all over the state. Once they are done "milking" the Salmon for the eggs, they want to give those Salmon away, free!
Just like their Pacific brothers, famous for returning to rivers along Washington, Canada and Alaska, the Kokanee Salmon in Colorado will die shortly after spawning. The DOW has decided that after milking the fish, they will give them away, rather than releasing them, only to die shortly afterwards. That way others can take advantage of the meat that the Salmon have to offer, instead of letting them go to waste.
That means that if you have a Colorado fishing license, and you're willing to drive to one of the pick up points, you could receive some free Salmon. The giveaways are, of course, first come, first serve. They are also dependent on the number of fish that are actually collect by the DOW.