I forgot my password/lost my key! What can I do to recover my data?

Nothing; you're screwed. (Apologies to Bruce Schneier).

If you have forgotten your passphrase, your only hope is that you chose a weak passphrase in the first place. There is an outside chance that you might be able to perform a successful dictionary attack to recover your passphrase. If you manage to recover your passphrase that way, then you may as well have not been bothering to encrypt your data in the first place, since a malicious attacker could have done the exact same thing to recover your passphrase.

If you selected a strong passphrase or lost your key file, you are completely out of luck. Nobody can help you recover your data.