You play a card X. What is the maximum number of cards that can be put into play as a result (including X) before you have to make a decision again?
I bid 81.
Have a big megaturn, gaining the last Band of Misfits, Golem, Herald, Copper, Silver, Curse, Estate, and having 9 copies of Throne Room in your deck. Make sure the only card in the supply costing $4 or less is Throne Room. Your hand consists of one BoM and 10 Golems. I denote any action card which doesn't have a choice by Z (if Z draws, it doesn't draw any action cards, unless I mention so).
The card X you play is BoM. You must play BoM as Throne Room (no choice) and must play Golem twice (no choice).
* The first play you find 2 Zs (no choice),
* The second play you find 2 BoMs (no choice).
** Play BoM as TR: play Golem twice, finding 2 Zs twice.
** Play BoM as TR: play Golem twice, finding first two 2 Zs, then 2 BoMs.
*** Play BoM as TR: play Golem twice, finding 2 Zs twice.
*** Play BoM as TR: play Golem twice, finding first two 2 Zs, then 2 BoMs.
**** Play BoM as TR: play Golem twice, finding 2 Zs twice.
**** Play BoM as TR: play Golem twice, finding first two 2 Zs, then 2 BoMs.
***** Play BoM as TR: play Golem twice, finding 2 Zs twice.
***** Play BoM as TR: play Golem twice, finding first two 2 Zs, then 2 TRs.
****** Play TR: play Golem twice, finding 2 Zs twice (drawing 10 Heralds).
****** Play TR: play Herald twice.
******* Hit and play Z.
******* Hit and play BoM: play Herald twice.
******** Hit and play Workshop: gaining the last Throne Room (no choice).
******** Hit and play TR: play Herald twice.
********* Hit and play Z.
********* Hit and play TR: play Herald twice.
********** Hit and play Z.
********** Hit and play TR: play Herald twice.
*********** Hit and play Z.
*********** Hit and play TR: play Herald twice.
************ Hit and play Z.
************ Hit and play TR: play Herald twice.
************* Hit and play Z.
************* Hit and play TR: play Herald twice.
************** Hit and play Z.
************** Hit and play TR: play Herald twice.
*************** Hit and play Z.
*************** Hit and play TR: play Herald twice.
**************** Hit and play two Zs.
Played: 10 BoMs, 10 TRs, 10 Golems, 10 Heralds, 40 Zs and Workshop, 81 total (if I can count)