This one actually consists of a lot of leg workouts, but a lot of exercises you do for your upper legs can work your gluts quite nicely as well! So kill 2 birds with one stone and try a couple of these out.
Squats.
Yes, you hate them and it's all you ever hear about but squats are great for your quads, gluts, and even your inner and outer thighs. Try these fun variations:
Wall sits: with your back to the wall, sit till your legs are bent at a 90 degree angle (sit even lower down to make this harder!). Hold it for 30 seconds, stand up, and repeat. See if you can do 45 seconds for the second set and 60 for the last one. Be sure to tighten your core, keep your hands off your knees, and keep your butt firm during the exercise.
One-legged: You can do this one of 2 ways. One way is to put a yoga ball between your back and the wall. Stick one leg out in front of you (it doesn't have to be too high off the ground) and keep your balance by tightening your core, gluts, and thighs. Slowly lower yourself down till your legs are at a 90 degree angle, hold for a moment, and roll yourself back to a standing position. The other way is to use a bar at about chest level. Hold the bar in both hands, feet on the floor beneath the bar, and raise one leg in front of you. Squat deep, almost till you're sitting (but not quite!), pause, and then stand up again. Do either of these about 10-12 times per leg, 3 sets/leg.
Sumo squats: Spread your legs slightly wider than shoulder level. Rather than having your toes point forward, point them outward slightly. Clasp your hands in front of your chest and squat. Tighten your butt, core, and thighs and stick your butt out a little as you go down. This might help with form and will really help you feel the squat. Do 3 sets of about 8-10 of these.
Jumping squats: Lower yourself into a standard squat (feet about shoulder-width apart, toes and knees forward, knees in line with toes) and jump. When you land, land directly back into your squat. 3 sets of 10-12 should get your heart rate up and your legs burning.
Lunges.
Like squats, also great for legs and gluts. Here's a couple variations:
Touchdown lunges: From a standing position, lunge one leg straight out behind you. Bending low on your forward leg, lean down and forward till you touch the ground with both hands on either side of your forward leg. Bring the back leg forward again as you return to a standing position. 3 sets of 20 per leg.
Squat lunge: Is it a squat or a lunge?? Go into a lunge position and pump yourself up and down about 20 times. Stand, switch legs, repeat. Again, 3 sets of 20 per leg.
Medicine ball lunge: Hold a light medicine ball or something that weighs 4-6 pounds in front of your torso. Lunge forward and twist your body toward the forward leg. As you stand, bring your body straight again. Lunge forward with the other leg and twist slowly an with control toward that leg, and so on. Take about 30 steps.
Thigh Squeeze.
This is a good one to help firm up that jiggle that might be going on between your legs. Lie on your back, raise your legs in the air, bent at 90 degrees (knees in line with hips), and place a yoga ball (or a few fat pillows) between your knees. Squeeze the ball/pillows as tight as you can while still keeping a steady breathing pattern and hold for 30 seconds. When 30 seconds are up, pump your knees (maintaining a grip on the ball) 20 times and the squeeze for another 30 seconds. Do 3 sets (Squeeze, pump, squeeze, pump, squeeze, pump).
Donkey Kicks.
Get down on all fours, knees below hips, hands below shoulders. If you have a heavy can, an 8 pound dumbbell, or something similar, it is highly recommended. Place the weight in your "knee-pit" (where your leg bends) and perform the exercise in one of the ways shown in the image. This one is a lot easier to illustrate than explain.
You can bring your bent leg up to hip-level and down (see image 1 and the lady in the orange), out to the side and down (like a dog marking its territory), in and out (2), whatever. Make up your own variation! Do about 3 sets of 20 of these.
Good luck!