I'm looking to make an alcoholic drink that has all the below qualifications:

Must be:
- Blue or purple
- Made without a blender (we have a shaker)
- Simple, easy to make
- Not too many components (we can only afford so much alcohol)
- Tastes great

- Vodka is a preferred ingredient but not necessary

What we already have:
- Ice Tea
- Lemonade
- Cola

We're looking for something that can be made in bulk to serve to all our guests.