When visiting activation.laptop.org your browser may say that the site cannot be trusted because the certificate has expired.
This is true, our certificate has expired. We don't plan to fix it.
We configure the browsers on OLPC OS to trust the site despite the expiry, so our activation and developer keys instructions normally work fine when using an OLPC XO. At least one version of OLPC OS was unable to proceed; for that version, you should use the collection stick method instead.
If you are using another computer, the certificate expiry needn't stop you making a developer key application, because you aren't entering any private or personally identifying information, only the serial number and UUID. Unlike most other sites, we do not capture e-mail addresses or names.
If you use wget to download a developer key on another system, you must add --no-check-certificate to the command.