Or to be completely offline, you can flip a coin 256 times to make the private key and have a calculator and pencil and paper to calculate the public key and address. I want to do it one of these days just to show that it's possible.
Calculating the public key would require a crazy amount of motivation
Calculating the address is impossible
https://bitcointalk.org/index.php?topic=286534.0Heh, I hadn't realized it was a recent topic on the forum.
I did say one could use "a calculator". Presumably, one could balance it being fancy enough to be able to handle EC math, while not being fancy enough that one had to worry about it storing ones key for a long time or getting compromised in some fashion.
And one would probably be more willing to enter one's public key on a "real" computer to hash to generate the address, though you'd probably want to use multiple systems to make extra sure that the address one generated actually corresponded to the public key. The network allows payments straight to public keys instead of addresses just fine, though I don't know of any wallet software that makes doing so simple.