Chris, or Oggie, as I knew him was someone I first met in September 1991, when he turned up as a new Queen's Scholar at Westminster. He was the year below me, but I always felt a bit young for my year, and so got to know him reasonably well. During the time at Westminster, we attempted to create a chlorate and sugar explosive in his back garden in Dulwich, he taught me how to "cheat" at Sim City. He was also responsible, I think (it's hard to remember things so many years ago) for teaching me some subtleties of the BBC Micro, and finally, in my last year at Westminster, for introducing me to C, and starting me on my current career with real programming languages.
When I started at Cambridge (after a year out), Oggie was in the same lectures as me. I met his friends, and they became my friends too.
In the years following my time at Cambridge, I'm ashamed to say I lost touch, but I'd heard about some of the things that he did, and kept reading his main blog, and his more frequently updated links blog (with its highly entertaining, and very Oggie-ish comments). I was amazed that at one party where I saw him, I didn't feel like a totally incompetent idiot anymore.
Oggie didn't go out of his way to make himself liked, but I admired and, despite all the jokes, did like him and to be honest he was one of the few people that have really inspired me. He was certainly one of the few to make me remotely competitive, though I could never honestly compete at even remotely the same level.
In the week or so following his death, James and his family have been stunning at looking after people. I was asked to help with the MySociety projects, and stepping into that was, in no uncertain terms, awe inspiring.
Words can't really express how I feel about this, but my thoughts go particularly to his family, to Helen, to Tom, to James and to Katherine.
Rest in peace, Oggie, you were a true visionary and you will be missed.
ETA: Oggie's full obituary in The Times