I identify with this so much. For a while I was trying all sorts of different root beers- just whatever I could find.
I'm a big Martinelli's sparkling cider fan. Doesn't need a lot of forethought or preparation, although I'm also HUGE on what other people have mentioned-- fruit juices in sparkling water, or San Peligrino's orange or lemon sodas.
Trader Joe's has a great selection of Italian Sodas as well.
Lastly, something I hear in my meetings- "What you think of me is none of my business" has made me comfortable to be a 32 year old man ordering shirley temples in a restaurant. Our eight-year-old selves were right, shirley temples are delicious.
Best of luck with the holidays!