Incense of Constipation: self explanatory.
Rod of Blunder: When used, it causes the wielder to fall prone or drop their weapon/staff/wand/etc.
King's Clothes: only idiots can't see them...
Sword of Prophecy: It tells you everything that happens to you five minutes ago.
Ring of Detect Thoughts: it informs you that anything you look at is either thinking, or not.
Headband: No mechanical bonus, but +10 to awesome.
+5 Axe of Empathy: Every time you hit something, you get dealt an equal amount of damage. Both you and the thing you hit are then healed the amount of damage dealt by the axe, even if either are dead. The Axe hopes you have learned your lesson.
Edit: @V: answered.