interesting tidbit regarding the "Jackpot" challenge......

[Mister Torgue Flexington]

it clearly states on the challenges log, that you must score either 3 Vault symbols or 3 Triple Eridium Bars on the slot machine in Sanctuary. I can never get it on there, no matter how many times i've tried, but yet, i've managed to get those (and complete the challenge) on the slot machine in the Badass Crater Bar in the Torgue DLC quite a few times.

Has anyone else gotten the same thing?

[K]

Well, the chance to roll triple eridium is roughly 0.23 % while the chance for triple vault symbols is 0.02 %.

[Mister Torgue Flexington]

true. but still interesting nonetheless

[Waste_of_skin]

Yeah, getting a "jackpot" on any slot machine anywhere seems to work. I've completed the challenge in Sanctuary, but I've also completed it on the slot machine in Dust, on the Flamerock slots, and even on a slot machine carried by a one-armed bandit (in Tundra Express, as I recall).