If you need a lot of ice but don't have enough ice trays for the job, grab some egg cartons and aluminium foil. In a few minutes, you can make a makeshift ice tray.
Picture: Fernando de Sousa/Flickr
WonderHowTo says you only need the bottom half of the egg carton, where the eggs are kept. Lay a sheet of foil and firmly press it into the egg pockets, because wrinkles will make it harder to release the ice later.
This is only a temporary solution though, and you won't be able to reuse it. Still, it gets the job done in a pinch.
Check out the full post below for other neat tricks with aluminium foil, such as making custom-sized tart pans.