I've always been a slimmer guy, I normally weigh ~160 lbs. The biggest I've ever been was when I was a Junior/Senior in high school and I weighed 170 lbs (I was working out 5 times a week).
Although I've stayed in decent shape in my four years since, I recently decided to start to take my health a bit more seriously. At the same time, I decided to go ahead and increase my "sexiness" and pack on some lean muscle while I was at it.
Here's the the workout regiment:
Workouts 3 days a week-- chest/back on one day, legs the next, and bi's/tri's/shoulders the next.
Here's the diet:
I eat as much as I can (I'm trying to gain weight). I'll have a cereal with a full banana for breakfast and a pasta for lunch. After a workout I typically eat a steak, spinach salad, and a full tomato. In between meals I try eat as much as possible (normally nuts, yogurt, small pizzas, etc.)
**** Gearing up for spring break (lawl), I've decided to add an EAS Myoplex protein shake to my after-workout routine. Lastly, I've started using SuperPump as a pre-workout supplement. This shit is pretty awesome... you feel like you can work out all day.
The results have been pretty damn good