If you don't want to cast it at that time (or you can't cast it, perhaps because there are no legal targets available), the copy ceases to exist
Wizards of the Coast provides Spelltable , a webcam-based tool that is a solid way to catch up and play Commander with your friends
In Europe, people still use these modified decks to play games such as Belote and Klaverjas, which originated in France and the Netherlands
For a 3-mana investment you can get two of something, whether its a utility creature, a game-ending threat or simply doubling up on interaction
Gaze of Granite is my favorite here, getting rid of all nonland permanents if you sink enough mana into it, and it's often more devastating for your opponents since you won't have many permanents on the battlefield at any given time