If they sell fireworks in your state, get yourself a gross of M80's or H100's, some duct tape, and pick up a bucket full of heavy rocks or some bricks and a big fishing net..
1. Secure explosive to rock or brick using duct tape (12 or 14 gauge wire works too)..
2. Light fuse (the wicks are water proof, so don't worry)....
3. Throw in water....
4. Scoop up fish with net and throw back the ones you don't want (carp, suckers, etc.)
5. Don't get caught 
The alternative method uses electricity, but is inherently dangerous..
Hehe reminds me of a joke I heard.
A game warden drives up to the boat launch one day and sees an old man loading his catch into the back of his truck. A bunch of other men are standing around admiring the the fish the man has caught and all of them are commenting on how he was the ony guy on the lake that day to catch any fish.
The game warden asks the old man, "How is it your the only person fishing today that caught anything?"
The old man looks at the warden and smiles and says, "Well that's an old fishermans trick I use and it works every time."
The game warden asks the old man if he could go out with him sometime and see and the old man agrees and tells the warden to meet him at 6AM the next day and he would show the warden how to really catch fish.
The next morning the warden meets the old man and they head out onto the lake. The old man drops the anchor, opens his cooler and grabs something to eat for him and the warden. Then he reaches under the seat and pulls out 2 sticks of dynomite. He lights one and hands it to the game warden, then he lights the other one and tosses it over the side of the boat.
At this point the warden starts yelling at the old man, "Sir you can't throw dynomite into the lake, it's illegal and I'm going to have to place you under arrest, the state is going to take your truck, boat, and all of your fishing gear as evidence, and your probably going to get some prison time as well for having explosives."
The old man looks at the warden, smiles, and points at the stick of dynomite in the wardens hand and says, "You going to sit there and yap all morning or are you going to fish?"