I know it's not a huge amount of funds in there, but I wouldn't like to think they're lost forever. Is there anything at all I can do to recover my passphrase? I don't remember anything about it 
You're stuck. If you had a really good idea of the password but were off by only one or two characters, a script supplied with Armory would help you recover the password. If you have no knowledge whatsoever, and you didn't make a paper or unencrypted (electronic) backup, you're stuck. Sorry. Please please please make a backup next time, preferably a fragmented paper backup but any unencumbered backup will suffice.