I do have an interest in it; I'd love to have some pieces memorised. I just don't have enough interest to sit down and work at it. If you have tips on making it easy, I'm all ears.
I doubt it would be even close to easy if you don't do it intuitively - its pretty simple though..
Memorise the score visually and theoretically - memorise the look of the keys played visually - memorise the sound of the notes.... conciously link them together.
Do this by...
writing out the score from memory -
Read the piece once, then attempt to play it from memory (small sections) - rinse and repeat
hear the notes in your head as you play - if you get stuck playing from memory attempt to find the notes by ear without looking at the score..
^no doubt qualifies as too much effort for you..
it works both ways though really doesnt it - I'm a fairly stella 'memorisor' / ear player - but my reading is pretty weak..