Have all three cards in play. Sacrifice Memory Jar and use Academy Ruins' ability to put it on the top of your library before ability of Memory Jar resolve, then draw seven cards. If you don't want or use some cards in your hand, you can discard them by Mind Over Matter. One for untap Academy Ruins, another for untap mana source like Tolarian Academy, Much Islands or etc. If you can produce many, many manas, you can use this process many time you want.

 

 

PS. You can use Mind Over Matter for tap some opposite's permanents, too. (Except enchantments and planewalkers)