I want to be capable of giving someone a small amount of bitcoin, in the form of a box (such that can be transfered through the mail or whatever). How can I do it, and make it as easy as possible for them to take ownership and start messing with it?
I've seen paper wallet where you just write a thing down, but I don't want to force them to type in a long key.
Most paper wallets include a QR Code (2D barcode) of the address and private key to save you from typing them in by hand. Some bitcoin wallets allow you to scan a QR code to sweep the funds out of it - I know blockchain.info's online wallter will let you use your webcam to scan a private key.
I'm not sure whether to try and answer your question, or to persuade you that this is a bad idea[1].
Computer-generated paper wallets are will be more secure (randomness/entropy) but if entering the code is prohibitive then you might consider a brain wallet, which let's you derive the public/private keypair from a passphrase.
The passphrase could be a personal holiday greeting. It's arguable whether the greeting would have sufficient entropy to prevent it from being guessed -- the consequences of using a weak passphrase are well-documented [2]. The brain wallet needs to be generated in a secure manner (offline -- anything you type into a web form is potentially saved/cached). Link[3].
Your recipient would then need to enter the passphrase into brainwallet.org (or equivalent) to get the corresponding private key. They really should do this offline too, so there is less chance that the passkey or private key are intercepted. Then they need to import the private key into a wallet client or web wallet.
As for transferring funds, you send bitcoin (assuming you own some bitcoin) to the public address you've generated for your recipients -- generating a public/private pair for them doesn't include the funding with bitcoin. If there is any chance that your recipients are not technically savvy enough to do the translations and import, then you probably don't want to actually send BTC and have it be orphaned. But that's your call.
I haven't covered all of them, but there are many other reasons why this might be a bad idea -- I'm tempted to abandon this response, but now I've invested too much time in replying. Caveat emptor, YMMV, IANAL.
[1] Bad idea for many reasons, but foremost, private keys need to be kept private. Sending them means they could be intercepted, possibly copied, and you and the recipient would never know.
[2] http://www.reddit.com/r/Bitcoin/comments/1nbmet/somebody_stole_over_13_btc_from_my_brainwallet_wtf/
[3] http://minetopics.blogspot.com/2013/02/super-easy-offline-bitcoin-wallets.html
Maybe try buying some dirt cheap 1Gb flash drives of eBay from China. Drop the wallet and a pretty instruction page that is stylized as a webpage or something. Very professional and flash drives are very cheap.
