Holy crap - a 35 second block - that has to be some kind of record!
naw, i saw a 20 second block once.
I remember a 14 second one. And it's not been too long ago.
And a 4 second one last year.
Shortest I ever seen was block 239570 found by slush on 2013-06-03 in just 2 seconds. Unfortunately it was invalid for us...
I guess there must be some minimum amount of time for a block to be seen by the network before the next block can be found?
I'm not sure about a minimum time, it was just that another pool found the same 2 second block and reported it to the network before we did.
My understanding is that when two pools find the 'same' block, they are actually finding different hashes that meet the difficulty requirement (please correct me if I am wrong). In this case, given that the network difficulty makes this so that the expected block length is ten minutes, and invalid blocks are not that common (IIRC, we have seen two in the last month or so), I am quite surprised that there should be such a 'collision' on a two-second block - surely the odds of this happening would be vanishingly small, unless there is something intrinsic that makes the difficulty on certain blocks much lower than it should be.