Oxymoron I encountered today:

"One-way Conversation" -- There is no such thing.  The definition of the term "conversation" requires that at least two people valued as equals are involved in a discussion where they present their ideas and feelings in an attempt to reach a mutual understanding.  A "one-way conversation" would be better entitled as a "monologue" or "soliloquy".  While the two differ in some respects, they both involve the ideas and opinions of a single person.

That is all.