I once made a Pun-pun in Champions. Using extra-dimension movement, base rules, and followers to abuse a power boosting ability that I can't remember anymore.

There wasn't a real limit, but I stopped when the character hit a 40,000point cosmic power pool.


In Rolemaster, I made an alchemist that made a ring of +5 levels to Item enchanting spells.
I used that ring to make a ring with +10
And so on and so on

Then I made a ring with +20k to ALL spells, then dominated the gods.

The Rolemaster abuse was the easiest one. I don't know what the heck they were thinking.