I don't think you can bulk much between now and Christmas. That's just four weeks. But if you want a mass-building routine, try this one. Most of it came from Jaster, but I put some alternative moevements in there because I wasn't a fan of some of the exercises (first number is sets, second is reps):
Day 1: Chest, shoulders and biceps
Flat or Decline Press 3x6-8
Incline Press 2x6-8
Military or DB Press 3x6-8
Upright Rows or Shrugs 2x8-10
Barbell Curls 3x6-10
Preacher Curls 2x6-10
Day 2: Rest
Day 3: Legs
Squats 5x6-10
Stiff-legged deadlift 3x6-10
Calf raise 3x8-15
Day 4: Rest
Day 5: Back & Triceps
Deadlift 3x6-8
Cable Pull Downs or pullups 3x6-8
Barbell or Dumbell Rows 3x6-8
Lying
Triceps Press 3x6-10
Triceps
Cable pushdown 2x 8-10
Day 6: Rest
Day 7: Rest