Just yesterday, started a modified version of a workout I did all through high school, which helped me get my bodyweight from 103 to 175 in about 2.5 years. Now, I'm back down to a measly 138, after not working out for a long time.
The routine does a 6 week periodization cycle, 3 weeks of increasing intensity, followed by 3 weeks of less intense, but with heavier weights (lower reps) to let your body catch up.
Basically, it's a 4 day per week: Mon = Chest/Back/Biceps/Abs, Tues = Shoulders, Legs, Triceps, Thurs = Full body, Sat = Full body
Every set is to failure (although I don't know about doing squats to failure anymore, THAT is a killer), you acheive different intensity levels by varying reps, sets, and rest between sets.
Has anyone tried a routine like this before? I know what you're probably thinking...OVERTRAINING. All I can say, is it worked like magic for me before, so I'm trying it again. In fact, I kept a good record of my bodyweight last time I tried it at the beginning of the year. Here's a chart that shows the spike in my weight (and then rapid decline after i had to stop working out due to moving and starting a new job).