This is a totally personal post (TPP, as I would call during future references).
Ever since I was a child, I had more than enough share of 'vendaikkai' (bindi or Okra) by my mom, saying it is good for my brain, esp. 'Kanakku nallaa varum'. I dont know due to which effect, I started loving maths from childhood.. Soon, numbers started occupying certain 'fixed places' in my memory and I could memorize upto 16x16 tables before my class 5. The numbers from 1 to 1K (upto 1024) are, to me, not just numbers but the members of a well-defined matrix. That helped me a lot whenever quick maths was required.. no need for calculators..
Some are my favorite, and to top all, 6. So many numbers that I got would invariably add up to give 6. Like Tendulkar, 'ten' became another favorite of mine, thanks to my nick name 'Padhu' or 'Pathu'. 10+6=16, which is my D.O.B. A few years ago, when I used to travel by auto in Bangalore, I would keep manipulating the passing-by vehicle numbers to try to get 6 out of them. Just to break the monotonous travel through familiar roads, u see..
Recently, whenever I do any 'routine' stuff, I parallel-process to get some arithmatic going. My favorite (memorable) numbers of late are 6,10,16,23,36, 43, 53,54, etc. each of them has a sweet memory associated with it (e.g., my hostel room numbers, '43'=Love you', etc.). When I wash the dishes, I would look at the quantity of the dishes and the watch and decide that 'OK.. I am going to wash them till this much minutes'. When I wash rice for cooking, I would start counting my 'squeezing rice' the sum of the hour and minutes.
In gym, I would burn 'one of my favorite numbers' of calories before switching to another machine.. While small-distance driving, I would look at the clock and decide, before this minute, I would be at this intersection/road.. During long-distane driving, it is reaching certain miles within certain minutes..
I never overly put any pressure on myself doing such things.. these all are done to convert the boring things into something new each time.. It has found to help me do such things more easily than before.. If any of you have any such 'time-pass' techniques, plz shoot..