the basis for the Time Gladiator movie?
If there's a Casino in the next episode I'll freak out.
There is a casino episode in the run with the Joker.....
S.
Part of Sister Flame's Clickey-Clack Posse
It's not a casino that's being robbed, but the JLU episode "Task Force X" (four episodes after "The Once And Future Thing") is very much a meticulously-planned heist of a well-defended area, told from the villains' point of view.
That's different enough.
Watching Justice League Unlimited
two part episode The Once and Future Thing. They go back in time. They have a fight with cowboys, then robots - no monkeys or ninjas. They even have a final fight in the Flavian amphitheater.
It is not exact, but the weird time travel, cowboys, robots and such totally made me think of Time Gladiator