Two of my favorite recipes:

Tropical smoothie:

1/2 cup FAGE 0% Greek Yogurt (fat-free)
1 cup light soymilk
1 cup frozen pineapple (or sub with mango/papaya)
2-3 packets of Splenda
1 Tablespoon honey

= 270 calories, ~26g protein

Chocolate/Strawberry Banana Peanut Butter:

1/2 cup FAGE 0% Greek Yogurt (fat-free)
1 cup light soymilk
1 small banana
2-3 packets of Splenda
2 Tablespoons sugar-free chocolate or strawberry syrup (like Hershey's)
1 Tablespoon all natural peanut butter

= 295 calories, ~24g protein