So it's slowly heating up out here in the Midwest, and I finally found someone who stocks soda cartridges. This brilliant confluence has led me to the holy grail of summer drinks: Sparkling Punch.
Classic punch consists simply of sour citrus, sugar, and rum, diluted with ice or water. Many variations have been made since, but there's a reason this one's classic. The best rum we've found for this purpose is Cruzan Dark; it's made in the Virgin Islands, so no import taxes, and it also doesn't advertise. Seriously, like ever. That's why you've never heard of it. That makes it cheap, and it's way superior to anything in its class. Obviously not top shelf, but come on, it's punch.
You will also need some kind of sour citrus. Lime is the most obvious, but you can swap some out for interesting fruits (pineapple, guava, pomegranate, what have you), and any other kind of citrus will work instead. Finally, you need sugar to sweeten. I highly recommend turbinado sugar for all purposes, but it's essential for this: nothing else will have the same flavor profile.
Make a quick syrup out of equal parts sugar and water. Squeeze your citrus juice fresh (it makes all the difference). It's also worth slicing off some peel from your fruits; the bitter compounds make a nice addition to the taste. Once your syrup is dissolved, put it in the freezer to cool down.
Now take your pitcher and pour in your fruit juice. Add most, but not all, of your cooled syrup; you should have about a 1:2 ratio between lime and sugar, but it mostly depends on your taste, so use a light hand and taste frequently. Now, pour in your dark rum to double the volume. 3 rum : 2 sugar : 1 lime juice, according to the ridiculous rhyme:
One of sour, (lime)
Two of sweet, (sugar syrup)
Three of strong, (rum)
Four of weak. (hahaha)
Now, your goal is to add as much rum and as little sugar as possible until it fits your taste. Let's be honest, who the hell wants fruit in their drink? I usually just start dumping rum in at this point until you can begin to taste its darker notes, then add sugar until the lime juice smooths out.
Now, add the pieces of fruit peel and toss your pitcher in the fridge. Once it's cool, you're ready to serve. Fill a glass with ice cubes, then pour your punch about halfway up the glass. Top it off with soda water (fresh from a seltzer bottle is really ideal; use premade only if you are too silly to invest in proper machinery). It's very light and refreshing, you can make huge quantities (really, quite huge) in advance, and it will get you drunk like you thought only champagne could.