Well, it's when I was round at a friend's house, around his pool. There were about 10 people, of mixed genders. We were playing truth or dare and I was dared to go into the pool naked and stay there. As no-one would see me, I agreed to it. But when I was in, the inevitable happened and they took my clothes (I should have seen that coming!) They were trying to get me to stay in the pool all night, but I wasn't having any of it, so I emerged from the pool, butt naked. They were all amazed at the courage, and although the girls made comments about the temperature of the pool causing considerable shrinkage, everyone was fine with it. They gave me my clothes back, but I didn't put it on again until I was leaving. Even if I say so myself, that took guts!
The other was a couple of weeks ago when I sneaked out at night, without a stitch on, and followed a country road (about 1 mile) to my old school and back. I was very aprehensive about people seeing me, but after a while I was getting quite cocky (excuse the pun) and dared to not hide from the next car that came. They were thankfully just guys on a night out and they honked as they drove past. So I got to my old school and did a lap of the track. I was exhilerated from the experience and even more so when I had to hide from a police car on the way back!!!