The Kingdom runs on booze, let there be no mistake. (Hey, you don’t have to be drunk to live here, but it helps.)
There are six basic boozes; gin, rum, tequila, vodka, whiskey and wine. All of these will give you 3 adventures and 3 drunkeness. When your drunkeness reaches 15 you can no longer adventure for the day. If you have Liver of Steel (from the Deep Fat Friars gate) you can drink until it reaches 20.
Basic booze isn’t very effective however and mixed drinks are better. To mix drinks you need a cocktailcrafting kit (from the market) or a bartender in a box (recommended). Mixed drinks give you 5-6 adventures and raise one of your stats by 8-10 points. They still give you 3 drunkeness. These are made by mixing a basic booze with another item, usually a fruit but some use soda water.
If you have the skill Advanced Cocktailcrafting you can combine a mixed drink with a garnish (obtained using the Advanced Cocktailcrafting skill) to create an advanced drink. These give 10-14 adventures plus 34-36 points to a single stat or divided among two stats. They give 4 drunkeness.
Here are the main drink recipies.
gin + grapefruit = salty dog (mysticality) + magical ice cubes = slap and tickle (moxie/mysticality)
gin + olive = martini (moxie) + little paper umbrella = a little sump’m sump’m (mysticality/moxie)
rum + grapefruit = monkey wrench (mysticality) + coconut shell = ocean motion (muscle/mysticality)
rum + strawberry = strawberry daiquri (moxie) + magical ice cubes = perpendicular hula (moxie)
tequila + lemon = margarita (muscle) + magical ice cubes = calle de miel (moxie/muscle)
tequila + orange = tequila sunrise (muscle) + little paper umbrella = ducha de oro (mysticality/muscle)
vodka + olive = vodka martini (moxie) + magical ice cubes = rockin’ wagon (moxie)
vodka + orange = screwdriver (muscle) + coconut shell = slip 'n slide (muscle)
whiskey + lemon = whiskey sour (muscle) + coconut shell = fuzzbump (muscle)
whiskey + soda water = whiskey and soda (mysticality) + little paper umbrella = roll in the hay (mysticality)
wine + soda water = wine spritzer (mysticality) + little paper umbrella = horizontal tango (mysticality)
wine + strawberry = strawberry wine (moxie) + coconut shell = pink pony (muscle/moxie)
As Zsofia pointed out, you can get drinks from the Barrel Full of Barrels. (Be carefull, some barrels explode.) The first two rows contain mixed drinks, the next two contain basic booze. Don’t bother with the last two.
The best place to get fruit for mixers is the Hippy Store. You have to either be wearing a Filthy Hippy disguise or have helped the storekeeper during the frat/hippy war in order to access it.
Hope this helps.