This is what I do....

...when I'm bored. Basically, I wrote down my phone number and found a 'unique'(?) way of remembering it. Here's how it goes.(some of you already know this - read Karan and Saurabh)

2nd digit subtracted from the 1st digit gives me the 3rd digit. The 2nd digit added to the 3rd digit gives me the 4th digit. The 5th and 6th digits, taken as a two digit number is the square of the 7th digit and the last three digits form the number of the bus which I have taken quite often to one of my clients location.