I was going in the Wayback machine to the old Six Flags websites, as I was bored. I stumbled upon the Six Flags Entertainment Card, which is something I have not once heard of.
If someone would have more info on this, it would be much appreciated. Can be found here
Going through the links, I was able to find the URL for the card issuer's page on the card, but of the few Wayback Machine snapshots I tried looking at, they all 302'd me. Nothing personal, but there are a lot of snapshots and I'm not checking them all, but here's the calendar:
From memory, since I was alive (and actually working at SFGAdv during the later parts of this card's existence), it was just another credit card where spending at Six Flags parks earned you more points than normal purchases and you could redeem rewards points for park tickets. I could be mis-remembering, it was a long time ago and I never had the card myself.