Got these weird plastic canisters that have single-serve packets of Grape Gatorade in them. Having to drink stuff like Gatorade as my doctor prescribed water pills to help get my blood pressure down (it's been really high recently with my psycho roommates making it difficult to so much as sleep). They were on sale at Safeway for $3 each (8 packets per canister), so I think it was a pretty good deal.
Just fill up a 20-oz bottle of water (if it isn't already full) drink a little off the top, pour powder in, cap it and shake. Enjoy.
Worked really well. Ends up I have a couple of these 20-oz Grape Gatorade bottles that I've held onto and washed which work perfectly for this. We have a refrigerator here with the cold filtered water thing in one of the doors which works splendidly as warm Gatorade is disgusting.