I don't know about anyone else, but I effin' HATE getting honked at whilst bike-ridin'. I can't help but get my hackles in a wad; basically, it's like someone's saying, "YOU DON'T DESERVE TO BE HERE. GET OUT OF MY WAY." As if this wasn't enough, you have no way to respond, no way to assert your rights to the road without resulting to shouting yourself raw or crude body language. Where's a commuter to turn?
MEGA BLAST HORN!
This little baby cost me two bucks at Kroger, and it's LOUD. Like, really loud. Once, I was riding behind some friends and blew it and they thought a semi was about to run them over.
So now, while I still can't stop people from being assholes, at least I can show my displeasure with them in a more vocal manner. If ya can't find it at Kroger (I somehow can't see it as being part of the normal stock, especially considering I found it in the soda aisle) try Walgreens or some Dollar stores. Or heck, order one online. Here's one for $2.39! Or if you want a louder, bigger version (the site says you can hear it from 2 miles away) try this site. Sorry in advance if you click on that one, the website is pretty obnoxious.