My group was pretty fond of Clarence the Talking Box, an item I found on the internet and dropped into a campaign probably about six years ago. It is still occasionally mentioned to this day.

That's pretty amusing ;p I may have to snag it as well :p

I had made a bow that was probably way overpowered but pretty fun to use. It was a longbow that held slots to place up to four wands. For each wand you added the bow gained an extra +1 to it's tohit and damage rolls (no bonus if no wands were in place). To use you simply tapped one of the wands and you can use the wand effect wherever the arrow hit. So you can shoot an arrow and have a fireball explode at the point of impact or shoot down a hall and cast an illusion wherever the arrow lands.

It was kind of fun to see all the permutations and uses my players could come up with depending on what wands they had at the time.

One of the NPCs in my game has a similar weapon. A crossbow that uses wands instead of bolts, it converts area effect into range touch with out a save. This could be a potently unbalanced weapon in a PCs hands so it has a couple of draw backs, it's spell trigger only and has a 10% possibility of a mishap each time fired.

My group has a set of Fibulae (Roman-style cloak pins) that let them talk to each other over any distance (must still be on the same plane of existence). What one person says can be heard by everyone who is wearing one. They quickly realized the tactical and strategic advantage of these items, and have treated them as more valuable than any magic armor or enchanted weapon.

Another group found an hourglass. When turned over and placed next to a character, it "turned back the clock" on any injury, poison, or disease, restoring them to whatever physical condition they were in about five minutes ago - even bringing someone back from the dead. Of course, each time it is used some of the sand vanishes, so it will eventually run out of charges. This item was specifically intended to aid the group when they were just starting and everyone was 1st level. As intended, it helped them survive those occasional "we did everything right but had some unlucky rolls" encounters. It will have run out by the time they gain a few levels and have more of their own resources to draw on.