Here is a link to a stability exercise that works your glutes (med and min but also some max).

This is a good summary of the exercises that produce the most activation of glute max but they do not necessarily avoid activation of the hamstrings. The good thing though is that they are very functional exercises so the strength you gain with these exercises will translate into strength on your feet during funtional activity.

This video shows the Bird Dog and Bridging. When doing the bird dog, if you turn your thigh outward, it will help to take the hamstings out of the picture, but you have to remember to keep the leg stretched out behind you, not drifting out to the side. With the bridge, the more you bend your knees such that your heels come towards your bum, the less your hamstrings can do and the more you can do with your glutes.

This is also a great exercise.

Hope that helps.