I don't know their story, but so far they are quite skittish and wary of humans. The bigger boy runs and hides whenever I move in his direction. The little boy is probably the most curious, so he overcomes his fear first and comes over to play with the latest toy or see what I'm up to on the machine that makes clicky noises. The girl is cautious. She will come near me, but then she'll just crouch and stare. She will tolerate being petted, but doesn't seem to like it, so I don't push it.
But I know from my flickr friends who foster feral and stray cats, especially Jimmy Legs (whose flickr stream is fascinating if you're a cat fan), that it can take a while for a cat to come around, and you just have to be patient and show them that people are nice and petting feels good. They're still young enough that I bet they can turn into affectionate kitties by the end of their stay.
So far the little guy is the only one who's shown much of an interest in the wet food I put out for them. He was like NOM NOM NOM NOM NOM. Big guy was like "nom nom OH SHIT A HUMAN RUN AWAY." Girl has not eaten so far. They have however all used the litter box correctly, yay! That's the advantage to having older kitties, I suppose.
They do need names. We're doing The Hobbit over on Mark Reads so I was thinking of trying to give them Tolkien names, but it'd probably look pretty weird to someone walking into the humane society to adopt them if their names were Luthien Tinuviel or whatever. Then again maybe they'd get adopted by Tolkien fans...
Hypatia would like everyone to know that she does not approve of these kitten shenanigans.