I'm on a rhubarb kick right now. (Yes, I do miss the inordinate amount of it growing in my mom's yard)
For outdoor summer movies, rhubarb vanilla ice cream is perfection.
What I do:
Puree some rhubarb (I do about 5 stocks, but if you want it weaker, do less~ stronger, do more) and then blend it with about a cup of ice (makes it like a slushie).
Fold in a thing of Vanilla Greek Yogurt (its seriously delicious this way as opposed to using the heavy cream needed for ice cream), sprinkle with cinnamon and cardamom.
I add honey to sweeten it (you could start by pureeing the rhubarb with about a 1/4 c. of sugar, if you'd rather); refreeze for at least a couple hours uncovered and enjoy.