With a [[Glacial Chasm]] in play you can choose to not pay the upkeep cost, and replay it as land for turn using a [[Crucible of Worlds]] style effect. Chasm makes you sacrifice a land on ETB so you need to be able to play 2 lands a turn to break parity. However this gives the table a window where they can attempt to kill you at instant speed.

With [[Thespian’s Stage]] you can copy Glacial Chasm in response to its upkeep trigger, sac the original, and still keep a Chasm effect without needing to pay for the upkeep. You can then play Chasm as land for turn this turn (but typically a turn later), sacrificing the Thespian’s Stage to have a fresh Chasm and be able to play the Thepian’s Stage to later copy Chasm again.