Alrighty, another stupid question by me. When I want to make the dolphin/whale shows, or build a "lagoon" type thing for jet skis and such, how do I do that? I've used to tools to make the hole in the ground, but it always ends up with jagged spiked rocks below the water. How can I make it nice and smooth, so that it looks like a normal pond or something like that? Please help!!

Lots of ways to do different things, such as if you want a technical hole dug with everything semetrical use the block by block and just drop down a say 10x10 about 3 blocks down and fill with water for squares and such, for more beauty and realism i tend to do ponds and lakes with the digger tool and just drop a spot of land down to what i want then you get jagged spikes- but to fix this just get the smoother tool out just look around for it, its there and pick a low spot with your mouse pointer and hold down and drag and it will all be one level smooth, or you can make mountian ranges and sorta make a creater like spot in the mountians and fill that up with water to make a tropical lake or just a fresh water lake in the mountians. if you have more questions you can put up another reply here or just private message me and ill be happy to explain it better.

Well, you have to put those rides on water...to start with...

xD
mostly the rides are above the water, at ground level.