Speaking of sleeper Freds (my first name is Fred, so, be nice now...) - I am 47, pretty fit, but my hair is nearly white - and if I don't shave, I look about 70+.
I almost always wear jeans - or shorts, t-shirt, etc. My bike looks beatup, like me - but it is a Cannondale F900 - which is a very fast MTB in my opinion.
Many a time I have destroyed roadies with that bike - for miles. As one told me when he finally caught up - "Do you know how bad it feels to be behind someone and just seeing the back of their white head as they pull away from you?"
Truly evil, I know, but fun.
I was a rock climber for a while in gyms - the others climbers would love to have the old geezer show some young teenager how to do the caves and such.
I love being a sleeper - it is a total "no lose" situation for me. If I go for it an win, well, that is a bonus, but otherwise? Well, what do expect from an old geezer...