It's used a lot in baking. I don't think chocolate chip cookies taste right without it!
You can also use it to flavor yogurt.
I use it mostly in baking but also in smoothies. One of my favorites is a smoothie of plain yogurt, coconut milk, melon slices, shredded coconut, a little sweetener, and vanilla.
Recently I found a recipe for a raw tomato salad that used it in the dressing (lime zest, lime juice, vanilla, olive oil, honey, sea salt). I definitely want to try it when the good tomatoes get here!
I experimented and threw 1/4 of a TEASPOON of vanilla in my coffee (with milk). Absolutely delectable for a blue moon occassion!