If you have a pile of dishes and are fresh out of dishwashing tabs, don't worry. There's no need to change out of your pajamas and head to the store. Chances are you already have all you need to make a good alternative.
Just put three drops of liquid dishwashing soap (Dawn, Palmolive, Fairy, that kind of thing) in the soap slot of your dishwasher. Then, fill the slot the rest of the way with baking soda and close it. Your dishes will come out just as clean as if you used a dishwasher tab.
Don't worry about a mountain of suds bursting forth from your dishwasher, either. I tried this tip on multiple loads and my floor stayed perfectly dry.
If you also need to do a load of laundry, but are out of laundry detergent too, there's a, as well.