Before I went to Cambridge University, I did realise that the chances were that I would come into contact with people who would do really important things and possibly a few who would be famous in the general scheme of things.
This has turned out to be true, I was at college with http://en.wikipedia.org/wiki/Hattie_Morahan. Rather ironically, I had loved the drama she starred in in 1996 and not known it was her when I met her at college, to be fair she was someone I barely knew, but I think she was part of the same group of friends as my room mate in the first year.
A good friend of my husband's father had won the Nobel Peace Prize the year before and was considered some kind of security risk.
There were many people we knew who were so friendly and level headed that you'd never know of their great acheivements, it took me years to realise the connection between and algorithm I'd learnt and a lovely old man I'd chat with at coffee.
For quite a while I had an office across the corridor from the guy who invented iris recognition and who was also some kind of advisor to my husband for his final year project. Again, you'd never have known from him what he'd acheived, nor by how he lived.
Somehow at Christmas 1999 one of the easier versions of the eternity puzzle http://en.wikipedia.org/wiki/Eternity_puzzle appeared at our house and we all found it rather tricky and pretty much laughed at the idea that anyone would solve the full puzzle and win the million pound prize. Turned out that the solver, only a few months later had been a fellow of my college and supervised me for two years, he'd left a few months previously "to do other things" it seemed he had no real plans and this piqued his interest. How quite such an intelligent guy could appear to be quite so scared of a group of 18 year old girls, I don't know!