We buy huge jugs of MSM powder. We keep a gallon tea jar and fill it with warm water every morning, and drop in a few green and black tea bags (and sometimes oolong), and just let it sit. It makes a mild tea. We add fresh lemon or lime when we pour a glass, and add a quarter tsp or so of MSM to every glass. We can drink an entire gallon or more in a day.
We also use Natural Calm. It's a powder that fizzes like alka seltzer. You add it to warm water and drink after it finishes fizzing. We use the original flavor which is very lemony, which we love, but there are other flavors with sweeteners. It's more easily absorbed, and one drink gives us 4 GRAMS of magnesium. A warm cup of magnesium every night has become a relaxing nighttime ritual.