Two guys decide to go ice fishing in Minnesota in the middle of winter. It's about -10° -- perfect conditions for ice fishing -- so they get all their gear and set out to a lake in the country. When they get there, the first guy goes to the edge of the lake (just a few feet from land), uses his tools to make a hole in the ice, sets up his equipment, and starts fishing. His friend goes to the opposite edge of the lake, cuts another hole in the ice about the same distance into the lake, sets up his equipment, and also starts fishing.

About half an hour goes by without a single bite on either of their lines. A kid -- about eight years old -- comes along with some fishing equpiment. The kid goes out to the center of the lake, cuts a hole in the ice, sets up his equipment, and starts fishing.

After just a minute of fishing, the kid pulls a fish from the water and tosses it in his bucket. A minute later, he catches another fish. Another minute later, he pulls out yet another fish!

The two guys, surprised and confused, walk over to the center of the ice where the kid is still fishing. One of them asks the kid, "Hey, we've been sitting here half an hour and haven't caught a single fish! Then you come along and catch several right away! How do you do it?"

The kid mumbles something and keeps fishing.

The first guy says, "What? I couldn't hear you."

The kid mumbles something again and keeps fishing.

The second guy says, "What? I couldn't hear you, either."

The kid sets down his pole, coughs violently into his hand a couple times, and says, "You've gotta keep the worms warm!"