Q: What should I do about my cat knocking over his water bowl?

My cat decided, for whatever reason, that he likes to tip over his bowl completely. I have tried so many different bowls. I have used a large one that gets heavy when filled and somehow he knocked it over. I used a "double diner" thinking that the dimensions would keep him from knocking it over...that didn't work. I always change his water twice a day so I don't think he's doing it because the water is stagnant. I have put the bowl in the bathtub while it's not in use for the past couple of weeks to at least keep the water off the floor and down the drain instead but I'd prefer to keep it out of there. I am thinking about purchasing one of the water fountains since it seems he likes the idea of moving water. Any other suggestions?