Weird, weird GPG issues

[Caleb Marcus]

It appears that there's something wrong with my public key... I can't
encrypt anything to it. On the command line, GPG says "no such user ID"
when I enter my email address or key ID, however, it shows up when I do
gpg --list-keys. I tried to send an encrypted message to myself with
Evolution, but the error I got was: "gpg: caleb.marcus at gmail.com:
skipped: unusable public key." Can someone try sending me encrypted
mail, or encrypting anything to me, to see if the public key that I have
published is somehow broken?
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