Nothing too crazy from me. I'm pretty vanilla. I get really into regular foreplay and standard sexual positions, so standard sex is pretty charged up and not boring.
To answer your question though, sex at work is about as crazy as I've gotten. I worked at a corporate office in a large building and had sex there after hours, when nobody or maybe only a couple of other people were around. The woman and I did not get caught. Another time, that woman gave me a blowjob in the elevator during work hours. Now that was a close call! As I finished, the elevator started moving, and the woman had nowhere to deposit the change I left. So, she had a full mouth, my pants were unzipped, and the door opens. We were eye to eye with one of our co-workers. I said hi, but she could only nod. I think we looked nervous, because he gave us a suspicious look.
When I was younger, I worked at a small retail store in the mall. I once had sex in the backroom. I was the only employee working at the store, so the front room was unattended. Anybody could have stolen anything they wanted and I would have had no idea. So, me and this woman are going at it and a customer starts yelling "hello??? Is anybody here?". I was on a mission to finish, so I went at it for another minute until I was done. The customer started walking into the stockroom right after we finished and he saw us both all sweaty and out of breath. He looked shocked and knew exactly what we were doing. Haha.
Okay, last thing. Was having sex with a stripper in VIP and she wanted a finger up her butt, so I stuck it up there pretty deep, while we did the deed. That's about as kinky as I've gotten though. Nothing crazy.