Hi.
I found 2 glitches while playing Minecraft multiplayer on my private server.
1) You can fully repair any item by droping them on the ground and picking them up again. (Easely done with the "Q" key)
2) If you drop and take any object from your inventory(like for the repair bug) and you disconnect right after picking up the item, it will create a duplicate of the item currently selected in your bar. The item will only have a quantity of one, and it will replace whatever is in the bottom-right slot of your inventory.
Ex : My diamond sword is in slot 1 and my diamond pick is in slot 2. I select my diamond sword by pressing 1, and then I press Q to drop the item. I take it again by walking over it and then it reappear in the slot 1 of my inventory. Then, I press 2 to select my diamond pick and I disconnect from the server. When I reconnect, I will have a duplicated diamond pick in the bottom-right of my inventory.
I don't know if it is the good section to post this or if there is a secret place to report bug.. if there is.. just delete this and please forward the information.