Very geeky skill. The numbers are the numbers on your cellphone keypad.
Jingle Bells: 333,333,39123,6666,6333,322329,333,333,39123,6666,633,99621
Twinkle Twinkle Little Star: 1199##9,6633221,9966332,9966332,1199##9,6633221
99 Bottles of Beer: 66611166666,9992229,6666,6666,1112236666 (repeat)
