How to be more interesting/spontaneous?

I understand that asking HOW to be spontaneous is the exact opposite of embodying the quality, but, yeah, I feel like I've become a boring person due to lack of social interaction. I don't go out as much as I did when I was in high school, but I'll be going to college in the autumn. I feel like I lack an interesting personality. How would you propose I become a more interesting or exciting person?