As said above, Deadlifts, squats etc. Deadlifts can add real quality mass to anyones legs.
As simple but highly effective home squat routine would go like this.
Squats - 5 sets, pyramided like this 20/15/10/8/6 - the first couple of sets are a warm up, use as heavy a weight as possible on the last 3 sets.
More squats - (1 Final killer rest-pause set)After the above halve the weight you used for your final set, and target 50 reps, if you cant get it rack the weight and take ten deep breaths before carrying on, only 2 pauses are allowed if you cant get 50 stick with that weight until you can then increase by 10-20lbs and start again.