I'll do two-a-days during a cutter, or maybe at the beginning of a bulking cycle, but that second workout will generally involve a small muscle group like calves or forearms, and I often throw in some cardio. But I steer clear of heavy, taxing workouts twice in one day. If you did legs today and arms tonight, then what are you going to do tomorrow? If you do back or chest/delts, then you risk overtraining the biceps or triceps since you blasted them already. Legs are out of the question.
Personally, I do a Push/Pull 9 day cycle.
Looks like this:
Day 1...BACK
Day 2...Off
Day 3...Triceps
Day 4...Legs
Day 5...Off
Day 6...Biceps
Day 7...Off
Day 8...Chest/delts
Day 9...Off
REPEAT CYCLE
Heavy weight....with lighter weight thrown in about once every third round. Eat like a pig, and sleep like a giant. Total, 100% gut-busting intensity.
Enjoy your days off---you'll need them. Have proper gear, and you WILL get large.

read the hypertrophy thread - why muscles grow. there are many great answers to training splits vs rest etc on there. Many of the mods had some really good points as well.

yes thats a great idea.you can loose your weight very easily.

I saw this topic header and thought you meant bangin' lol

Very rarely - I may add in more body parts on workouts but once I shut down to rest I'm done for the rest of the day.

There are a number of guys I've read about that train split bodyparts regularly. Just let your body tell you. I just know that I will push into overtraining if I do.

Hell ya bro! Obv limit yourself ,but protein synthesis is increased while on cycle and u recover A LOT faster than u do naturally, so ur gtg!