Rated R, huh? So we could kill a bunch of people, curse quite a bit, and do drugs, but need to be careful about full-frontal nudity, especially if sexual content is involved?
Sounds like a bit much for me.
Seriously, though, if it weren't a rather expensive first date, skydiving would be fun. Rafting is a good one, but can be a bit long if you don't know how well you will get along.

I used to make my first dates go on a hike with me and climb Lockegee rock, where you had to climb a sheer rock wall, using toe and handholds. If they couldn't keep up, or complained, there was no second date.
I actually found a great three-year boyfriend that way.

First date - usually I want to talk, so a dinner or a walk. Second date, however.. IF there is a second date, is the time for adventure. I've gone to the nude beach for a second date. I'd love to try skydiving too.

Well, the wildest thing I have ever done is meet this awesome punk rock girl (I was about 22 and she was 21)...we walked out the door with under 20 bucks and didn't come home for several days...it was a blast...shows, random houses, fights and so many laughs...still had money in my pocket when I got home...

First dates are for getting to know each other. If you are busy, in motion, on a ride, out of breath from physical activity how can you talk. A quiet dinner is more appealing to me. Now a second date is a different story.....

Getting in the ball pit at a chucky cheese. Pants are optional.

I'll go out on a limb. I work with clay. I specialize in making pots on the Potter's wheel! Now, you imagine the rest...? Is that enough to earn an 'R' ??

Just going on an actual date would be adventurous to me. I have been single half my adult life, including now, but l haven't been on a real date since the early 80's. It has been meet and hook up or acquaintances that eventually turn into more. An actual ' I'll pick you up at seven for dinner date with someone you just met is to much pressure.

Been a while but I think going out for a cuisine one is not familiar with is always a lot of fun.

Anything that won't get me killed

Skydive or an anonymous "Eyes Wide Shut" situation. Either one is fine with me.

To me the most adventurous thing would be to do whatever it takes ( nothing less, nothing more) to make sure I will stay on board for a second date

Show up

Since custom dictates that we categorize a first planned occasion to get acquainted a 'date' I'd have to admit to nothing much adventurous. I like activities that allow for conversation #1 and perhaps some distraction with a game, something like bowling or pool or even making that first get together include some other people such as another couple or even some family. How we play games and act among others socially reveals a lot to the observant.

I personally define dating as a next step people already acquainted on some level decide upon for a closer look and potential romantic consideration; whereas an initial meeting is way before interest in intimacy can be determined because people don't even know one another yet.

It probably sounds a bit 'hair splitting' or crazy to some but detailed explanation takes in more explaining than a little comment box ought to include. Nice thing about this kind of site and format is that it enables members to learn enough about one another to satisfy some curiosities before the first in-person meeting, makinig it less of a 'cold call' than a typical 'blind date' meeting. And, by the way, how many of them can be disastrous due to zero knowledge about who the other person is?

Fly to Germany.

Just sitting on a hilltop gazing at the stars and .........

I went to a swingers club on the first date once. Ended up dating her for like six months. It was all fun and till I developed real feelings for her. Then I couldn’t handle the fact that she was married and was fucking other men on the side. Which I knew going into it.

Dinner and a movie of her choice. The conversation would allow us to see if there is a spark. Her choice of movie would also say a lot. But if she wanted to go skydiving I'd be down with it. It's a major adrenaline rush and the conversation, or more, would be totally free form. It's hard to explain if you've never jumped but you feel so free and alive that everything seems better.

Go to an R or better rated art movie like:

Anything is possible as we are both adults.

Go to a theme park?