How about a stack of four event cards, only one of which is visible at a time. I didn't clean up the wording too much, so there may be some wording issues.
Summer$0
Once per turn, choose one:
- +1 buy. After your cleanup phase, draw seven cards and discard one. Put a +1 Draw token in play (Duration: while in play, all players +1 draw. This token is removed when the Season changes.)
- Name an Action card. Look through your discard pile and set one copy of that card aside. Play that card at the beginning of your next turn. Put a +1 Action token in play (Duration: while in play, all players gain +1 Action. This token is removed when the Season changes.)
- Put Fall event card on top of this Season deck.
Fall$0
Once per turn, choose one:
- Look at the top five cards of your deck. You may trash up to one card, discard up to one card, and put the rest back in any order.
- +3 coins. All other players gain +1 coin.
- Put Winter event card on top of this Season deck
Winter$0
One per turn, choose one:
- Put a Counter Attack token in play (Duration: while in play, when an Attack is played, it doesn't affect you. This token is removed when the Season changes.)
- Put a card from your hand on top of your deck. If you do so, every other player discards one card. This is not an Attack.
- Put Spring event card on top of this Season deck
Spring$0
Once per turn, choose one:
- +2 buys. The first card you buy this turn may be put on top of your deck. Put a +1 Buy token in play (Duration: while in play, all players gain +1 buy. This token is removed when the Season changes.)
- +1 buy. Gain a card costing up to $3. You may put it on top of your deck. All other players gain a copy of this card.
- Put Summer event card on top of this Season deck