There's a jpl service kicking around that's on telnet and is fun to play with. Nothing requiring a password - it's published material, essentially a website, but in command line form. Presumably the anon account permissions would take some care to set up, but once that's done it's a good interface, I think.
IIRC, the Telnet interface is technically more fully-featured than the others, although that's probably simply because it would have come into existence first.
