How about a new Interactive Special called the old fishing hole. You pay products to get in and fish. Fishing will get you either fish or random building materials. Each position in the old fishing hole provides a different quality of material. For example the worst spot gives you bricks. Second-worst gives you slabs. The best one gives you barn expansion materials. At all spots you can get fish. The spots are not static but change every few hours so the best spot is not always in the same spot.