You look at a foe's hand, and you can cast them this turn with mana of any amount counting for that
You can always "bracket decks up," meaning you can note that your deck meets the description of a Core (Bracket 2) deck but plays like an Upgraded (Bracket 3) deck, so you should bracket it at Bracket 3
During their main phase, a player can roll the planar die
It doesnt have many applications outside of EDH unless you wanted to get really spicy with Sorin, Imperious Bloodlord in Timeless, but in EDH it chews away at your opponents resources with a few clones
Some spells have text that allows you to choose the same mode more than once
If your commander is Trostani, Selesnyas Voice or Ghired, Mirror of the Wilds, your Commander even has a built-in way to abuse Sance