My favorite are frozen blueberries. They are delicious, and LOADED with lots of good nutrition. I buy these 5 lb. bags @ Costco for around $7. Another benefit, frozen fruits don't go bad in the crisper drawer.
I like to serve them up in a little bowl. One serving (3/4 cup) is only 80 calories. By serving in a smaller bowl, it makes me think I've had a whole bowl of berries.
I have friends who love smoothies, and that is a nice way to sneak in fruits and vegetables. My only concern is whenever you blend, it takes A LOT of fruit, ice cream, or whatever to make a small shake. I'm always amazed when we make brown cows, how much ice cream is in each shake. For that very reason, I shy away from drinks of the blended variety. If you HAVE to have ice cream, stick to a small scoop served in one of the cute little bowls.