I've been on this program for 3 weeks so far. Here's an update.

I pulled this routine from Super Squats: How to gain 30 lbs of muscle in 6 weeks and changed it slightly.

Twice a week
Dumbell shoulder press 10x2
Dumbell bench press 10x2
Squat 20x1
Bent-over Row 12x2
Standing Curl 12x1
Calf Raise 20x2
Ab Crunch 25x1
Heavy Hammer (ironmind.com) 12x1 each arm

Since it's a weight gaining routine, I'm also eating as much as possible and drinking at least 2 quarts of milk daily.

At first, the only problem I had with the 20 rep squat was feeling like I was going to pass out. After I focused on breating more, that went away.

Now my problem is the weight on my shoulders cuts off circulation and my arms go numb i.e. fall asleep, making it tough to complete the 20 reps. If I can't complete it, I'll do another set. I'm going to experiment with arm and elbow position and see if I can't fix this problem.

Regardless, I'm making good gains. 12 pounds so far and lots of strength gains too. The gains are slowing down now, I'm only gaining about a pound per workout.