I tell ya what, the Edinburgh fringe with 2 or 3 mates, one of whom is unstoppably extrovert on JUST this side of being really annoying with it, and all of you being somewhat under the influence for almost the entire duration, is a good way to get your count up.
Thanks to that we have at the very least (from what I can pick out of the alcohol-soaked haze) made nuisances of ourselves to Dean Haglund (the long haired one out of The Lone Gunmen) once, Mark Watson a couple of times (one instance of "digital heckling" which ended in the temporary confiscation - by Mark - of one of the quieter mates' camera, another just a chat as he hung around ninja-like in the audience before a different show), Chris Neill at LEAST twice (bbc radio producer/sometime on-air comedy performer) and a variety of others. All cool guys. Possibly Tim Vine (also cool) as well ... or maybe we were just up close at a show and were within touching distance. Same story for Nicholas Parsons who was quite fractious once off stage. Alan Davies, disappointingly, wouldn't even give you the time of day.
Additionally I have corresponded with a couple of moderately famous musicians in a meaningful manner over email and the like (Ricardo Autobahn who keeps popping up in different places, including a UK eurovision entry in the year of Lordi, and M J Hibbett who is a favourite of certain radio 2 / r6 DJs) and met the latter very briefly (handshake I think?).
Oh yeah. And an ex-gladiator (Khan) was a doorman at a nightclub I worked at for a couple of years. Still had the physique, you wouldn't dare mess with him unless you were very drunk AND very stupid. Good bloke but quite taciturn.