Black and Purple Cow

For the Black Cow, simply add vanilla ice cream (float style) to your favorite rootbear.
For Purple Cow, simply add vanilla ice cream to grape-flavored soda.

There are endless combinations you can play with. Here's a few.

Coke float. Like it sounds, float your favorite ice cream in coke.
Chocolate over- load. Chocolate icecream covered with syrup, floating in coca cola
Dr. Moo. Dr.Pepper with vanilla icream and your choice of syrup (cherry and or chocolate are best).

Try your own, and tell me about it.