In hoodoo, a mojo is a sacred bag, filled with symbolic items and worn around the neck. Back in the day, we attached charms to our handlebars and referred to them as bike mojos.
A bike mojo could be just about anything, but in order to have any true meaning, it had to come to you unbidden. In other words, it could be something you found (but not something you sought), or something given to you (but not something asked for), just so long as it held some significance for you.
A mojo was not just decoration, but it was also a combination of good luck charm, prayer flag and personal identification. At least, it was all of those to things to me.
My favorite mojo was a molded plastic medieval warrior, carrying a blue shield (but missing his sword), 3-1/2" tall, which I found while riding my cross bike, one day. I zip-tied him to the front brake cable housing on the Avail, and transferred him from cross bike to cross bike until I eventually sent my last cross bike to Charles, as a single/fixed racer. The warrior, whom I always called Arthur, now resides on one of my toy shelves.
Another favorite was a small tiki god, from Hawaii. He was almost a cheat, as I did ask for him. But, I reconciled that with the fact that I didn't plan on putting him on the bike when I did ask for him. He ended up on my M2 StumpJumper after living on the top of my dresser for a few months, with no purpose. But, possibly reflecting his sketchy status, he was lost during an urban night-ride in the Denver Tech Center.
Carol had a Teletubby on her bike, for a while, which she found on the street near Crowfoot Valley Coffee, in Castle Rock.
Other people in the bike shop had a variety of found strings of beads, friendship bracelets, etc.
The last mojo I attached to one of my bikes was on my fixed gear commuter. It was a studded dog collar-style bracelet which I found on Lincoln Avenue, as I was riding downtown to do some watercolor sketches of a big church I had noticed a while before.
No, wait, I take that back...I have a broken bracelet of some sort on the RockCombo handlebar.
Old habits, I guess...