I don't necessarily follow any specific recipe - I like to experiment. I haven't made any with yogurt, but I've been meaning to try some of those ideas. Right now, I like to use a good fruit juice blend as a starter, and then add in the fresh fruit. I'm hooked on this one at present.

10-12 oz of V-8 Splash tropical blend. (It's a blend of apple, pineapple, kiwi, mango, and lime juice.)
One fresh banana.
One cup of fresh or drained canned pineapple.

Toss all in the blender at high speed until well blended. Pour over crushed ice, or drink as is.

I also like the V-8 Splash strawberry banana blend juice. Same as above - only add banana and strawberries.

I also like to take and pour the mixture into paper cups and freeze. You can either break up the frozen mixture and eat in chunks since it won't freeze rock hard with the fresh fruit in it, or toss the frozen mixture back into the blender just long enough to break it up so that it's like a slushie. It's really good that way as a nice icey drink on a hot day!