Having sex in tent. This is creative, but do-able? I guess have to look for some very private place to do it, very adventurous. There is another suggestion for having sex on the beach, I think you may use tent if you are not comfortable to do it at an open space. It's dangerous as well, plan and research before you go for it else you will be regret for life. Who do not wish to have sex under the stars and moon, and the sea breeze is definitely a place that can make her climax again and again.
In a car, yes, this is do-able and adventure. It's not as comfortable as having sex on the beach as the space is limited and it's not under the sky. But MPV can change all these. You can have sex anywhere you want, beach, woods, parking lot, lake side, and you can even have a mattress in your MPV to make your partner more comfortable during sex. If this is possible, get a panoramic view and you are as good as having sex under the sky.
Having sex in the shower. Most of you out there sure tried it before, even though it's not as adventurous as other suggestions here but it is still one of the best place for sex. Wait no more and go for it now.