Imperative expression used to mean "go for it!", "get started!", "it's yours now, run with it!".
Used frequently in TV shows in front of a live audience when ceding center stage to a guest performer/contestant (impromptu or not).
from pulp fiction
host:-Ladies and Gentlemen, the moment you've all been waiting for... The world famous Jack Rabbit Slim's Twist Contest!
Now let's meet our first contestants here this evening...
Young lady what's your name?
uma:-Mrs. Mia Wallace
host:-And how about your fella here?
john:-Vincent Vega !
host:-Alright, let's see what you can do... take it away!!