If I were? is a simple activity to practice the second conditional‏‎ and it can, with some adaptation, also be used to practice other conditionals‏‎ forms.
Preparation
Prepare a few flashcards‏‎ on which you have the name of someone or something which would fit in suitably to the conditional sentence:
If I were… I would…
For example:

President of the USA
rich
a…