The easiest ways to get natural magnesium, at least for me, are these sources:

1- Pumpkin seeds. Just keep a bag around and snack on them. Very rich in magnesium.
2- Soba (Japanese buckwheat noodles) Easier to get in Japan, but available in the US (try Amazon for example). These noodles are packed with magnesium and make a super-healthy alternative for pasta.
3- Mineral water. There are a couple exotic brands that are high in magnesium, but the widely available San Pelligrino is pretty good. If you drink bottled water, try switching over.

And yes, the calcium magnesium balance is something to consider.

Thanks for the good post.