Casino jackpot models
First of all, the fact that you are mixing the use of Jackpot and MultiJackpot in this way suggests that they are really 2 different instances of a common, underlying concept. That calls into question whether they really need to be implemented as two different models. But that's up to you; you know the specifics of your own application.

As for removing the duplication, how about something along the lines of:

games     = ['Caribbean Stud', 'Progressive Blackjack']
@jackpots = games.map do |game|
  [Jackpot.where(...),
   MultiJackpot.where(...)]
end


You end up with an extra level of array nesting in the results, which could be eliminated with flatten(1). Or if don't mind adding your own methods to Array, I like to add one called mappend... I find it useful in almost every project. It it like map, but it appends all the returned arrays together to form a single array.

If you need the names of the games together with the results, you can games.zip(@jackpots) (you need the extra level of nesting for that one).

As for the DB calls, you'll find it hard to work around that while still using your nice Active Record query helpers. When DB performance is critical, I usually end up rolling my own SQL, perhaps using custom helpers added to model classes.