Spice it up

So my boyfriend and I haven't been together for very long. Only about four months total, but I've known him for three years and we both admitted that during those three years, there has always been something there. Anyway, I want to so something special for him to make our sex life more exciting. Like I said, we've only been together for a short amount of time and we've only had sex a handful of times. I just want to spice it up a little, make it more exciting. Any advice?