I've only been to Rome once, and it was during the winter. But if I ever visited in the summer...boy howdy...this would be the first thing I'd drink.
People love drinks where fluids of two different colors lazily mix in the glass, and that reminds me of Italy. There seemed to be a lot of people just sitting on benches and enjoying life.
In the US, I think a lot of people would stir this drink. Don't do that! It IS the most efficient way to evenly mix the drink, but you're missing all the art as that red liquid slowly unfolds--creating a show that has never been seen before and will never be seen again in exactly the same way.
It also creates a drink that has never been seen before. Don't believe me? Google it. This is an original baby.
Combine vodka, lemonade and limoncello in a cocktail shaker with ice
Fill a tall glass with ice, strain lemonade mixture into glass
Combine raspberry liqueur and simple syrup in a glass, pour into cocktail. Serve
Combine all ingredients in a small saucepan over moderate heat
Bring to boil, then reduce to a low simmer
Cover and simmer ~1 hour, stirring occasionally, until syrup is bright pink and coats the back of a spoon
Strain, discard rhubarb stalks, and store in an airtight container in the fridge for up to two weeks