Dan- that's me in the front seat of my Citabria. A $100 hamburger is an old pilot term for taking the airplane for a cross-country trip to an airport with a good restaurant just for the hell of it- once you add up the fuel and other costs your hamburger ended up costing $100 (or more!)
The Citabria, unlike most airplanes, is not equipped with wing flaps. Flaps are basically extensions to the trailing edge of the wing that increase the amount of lift and drag generated by the wing, which basically allows you to point the aircraft at the ground without increasing the airspeed. This is very helpful when you need to slow the airplane to land.
In the case of airplanes without flaps, you do what's called a "side slip" - you deliberately yaw the airplane with the rudders so the nose is pointing a few degrees away from the flight path, and use opposite aileron to keep the airplane from banking in that direction. Doing this exposes the side of the airplane to the relative wind, which creates enormous drag, and also makes it possible to see the runway out the side window, which isn't always easy with a taildragger airplane operating at a high angle of attack.
You kick the slip out and fly "straight" just before touchdown.
Notice also that the altimeter is at 500 feet: field elevation is around 420. The airspeed dial just to the right of that shows about 75 MPH, which is about 10 MPH too fast (which is why I'm slipping the airplane). You can see my left hand on the throttle ready to add power and go around if anything goes wrong on final. The big red knob is the fuel mixture control. The little circle in the window is an air vent that blasts cold air on your face, this is very helpful when doing aerobatics as you tend to get pretty warm.
(Lest I incur the wrath of the other pilots here I'm actually lining up for the GRASS runway, not the hard-surface . . .)