Since beta 1.3 I've only seen 2. That's never stopped me from spawning them...but legitly i've only found 2. The first
time was when I was a noob at minecraft and was building a house...then it crawled up it and fell through the roof
as i hadn't finished building it. Then I ran for so long and I couldn't find my house again...the second time was
on a server.
I've seen only a handful. But to be honest, I only clicked on this thread because I hoped it would say "How many spider jockeys does it take to screw in a light bulb?" And then we would all come up with silly answers and laugh.
I have seen two or three. Haven't had to engage one.
Say one or two out the window/when I was on the roof.
And one when I was in classic getting a picture of my coast-to-coast sugar cane farm. I have a picture or two of him.