What's the easiest RDF syntax to write ontologies by hand?

You're not crazy, just eccentric :) Actually, I typically write my RDF by hand as well (Turtle or TriG syntax, using VIM with syntax highlighting). But to be honest, I usually only do this for models of "managable" size (where "managable" is a function of how many other users have to co-edit, the number of classes and relations, and the number of OWL restrictions I need). For more complex stuff I tend to use TopBraid Composer.

N-Triple

When i need to create (simple) ontology by hand, I prefer MS Excel (for quickly separating three columns, and a forth column be the terminating . )

• text processing,
• quick copy paste columns,
• Row Filter - to see only one subject, predicate or object :P

Finally copy paste this within a text-editor and replace tabs with whitespaces. You are done.

(Protege just kills you in productivity)

RDF + easiest + by hand = Turtle

I guess the easiest syntax is the one you are more confortable with. It is a question of taste but also of tools. For instance, using RDF/XML can be convenient because most text editors have some built-in XML-related functionalities. I personally edit my ontologies in RDF/XML in a text editor, and I'm quite confortable with it (no joke!). But I admit that RDF/XML is cumbersome and I tend to use Turtle when it comes to communicating examples (in emails, forums, semanticoverflow, etc). Now there is an official OWL/XML syntax [1] which is probably quite nice but I've not yet taken the time to look at it in details. You can take a look at a screencast showing how OWL/XML plays nicely with XML tools [2].

• [1] OWL 2 Web Ontology Language - XML Serialization. W3C recommendation. http://www.w3.org/TR/owl2-xml-serialization/
• [2] Tour of OWL/XML. http://www.youtube.com/watch?v=Hn-8_J5JGPA

I personally prefer Turtle for writing stuff by hand, for editing it I've recently written my own editor - named simply rdfEditor - which I hope to release in the next month or so. It provides syntax highlighting, auto-completion, validate as you type and various export features.

There is a screencast at http://www.youtube.com/watch?v=upY-Vpte8OI but the quality is rather iffy as I didn't have a very good video capturer/mic to make it with (looks best at 1080p full screen and is somewhat unviewable at standard resolutions)