Simple acquisition drill: take a few paper plates and color them different colors with sharpies / whatever. Staple them up. Have someone else call out colors to you and engage. Add in reloads, transitions, etc as you like.
To make it more complex, cut out different shapes of the plates and color them different colors. Have your #2 guy call out a color and engage all shapes those colors. Or have him call out a shape and engage all shapes regardless of color. Finally, have him call out a specific color of a specific shape. I like these drills because it adds cognitive thinking into the mix and they're extremely simple, plus the variations are unlimited. You can add in high intensity exercise to get your heart rate up, shit like that.
