You Are Listening to Los Angeles is a website that does an unusual mash-up-- police scanner plus ambient music. It's oddly hypnotic and while most of the time nothing is really happening, every once in awhile you'll hear something interesting occur. If you need to brush up on your police codes, here's a handy guide to LA County Sheriff Codes and LAPD Scanner Codes:

Los Angeles PD Radio Signal Codes

from PoliceScanner.com

LOS ANGELES COUNTY SHERIFF OFFICIAL CODES:
187 Murder 261 Rape Vicinity
207 Kidnapping 261-A Attempt Neglect
207-A Attempt Kidnapping 273-A Child Neglect
211 Robbery 273-D Wife Beating-Felony
211-S Robbery Alarm-Silent 288 Sex Crimes Against Children
217 Assault-Murder Intent 314 Indecent Exposure
220 Assault-Rape Intent 330 Gambling
242 Battery 374-B Illegal Dumping
245 Assault W/Deadly WPN. 390 Drunk
246 Shooting At Dwelling 390-F Drunk, Possible PCP Use
415 Disturbance 459-A Burglar Alarm-Audible
415-A Disturbance In Auto 459-S Burglar Alarm-Silent
415-B Disturbance- Business 470 Forgery
415-C Disturbance- Party Crash 480 Hit & Run- Felony
415-D Disturbance- Drunk 481 Hit & Run- Misdemeanor
415-E Disturbance- Party 483 Hit & Run- Parked Vehicle
415-F Disturbance- Family 487 Theft- Grand
415-G Disturbance- Gang Fight 487.2 Purse Snatch
415-J Disturbance- Juveniles 488 Theft- Petty
415-S Disturbance- Neighbors 488-B Theft- Bicycle
417 Man With Gun 502 Drunk Driving- Misd.
417-A Man With Knife 503 Auto Theft
417-S Barricaded Suspect 503-A Recovered Vehicle
447 Arson 504 Tampering With Auto
459 Burglary 504-A Car Strippers
510 Speeding Or Racing 902-A Attempt Suicide
586 Illegal Parking 902-H Enroute To Hospital
586-E Parking-Block Driveway 902-N Traffic Accident-No Inj.
594 Malicious Mischief 902-R Rescue Responding
597 Cruelty To Animals 902-T Traffic Accident-No Details
601 Incorrigible 903 Airplane Accident-No Details
602 Trespassing 903-L Low Flying Aircraft
604 Throwing Missiles 904 Fire
647 Vagrant 904-A Fire-Auto
647-A Vargrant Loitering Near 904-B Fire-Brush Or Grass
School Or Public Place 904-G Smoke Investigation
653-M Lewd Or Threatening TX 904-I Illegal Fire
901-N Ambulance Needed 904-S Structural Fire
901-S Ambulance Disp.-Inj. 904-T Fire-Trash
901-T Ambulance Disp.-Traffic 905-B Animal Bites
902 Person Sick Or Injured 905-D Dead Animal
905-N Noisy Animal 916-C Citizen Holding Felony Subj.
905-S Stray Animal 917-A Abandoned Auto
905-T Vicious Animal 917-S Suspicious Auto
909-A Hot Wires Down 918 Insane Person
909-T Traffic Hazard 919 Keep The Peace
911-A Contact Informant 920 Missing Adult
911-B Contact Officer 920-A Found Adult
911-C Contact Citizen 920-C Missing Child
911-N Do Not Contact Inform. 920-F Found Child
912 Are We Clear? 921 Prowler
913 Are You Clear? 921-P Peeping Tom
914-N Concerned Party Notify 922 Illegal Peddling
916 Officer W/Mids. Subject 923 Illegal Shooting
916-A Officer W/Felony Subject 924 Station Detail
916-B Citizen W/Misd. Subject 928-B Found Prop-Bicycle
924-B Notify Dispatcher 928-L Lost Property
925 Person Acting Suspic. 929 Person Down
925-A Person Susp. In Auto 929-A Person Down In Auto
926 Tow Truck Needed 930 See The Man
926-A Tow Truck Dispatched 930-A See The Manager
927 Suspicious Circumstance 931 See The Woman
927-A Susp. Circumstance Person 995 Strike Trouble
Pulled From TX 996 Explosion- Non Criminal
927-B Susp. Circumstance Open 996-B Bomb Explosion
Door Or Window 996-T Bomb Threat
927-C Check Vicinity 997 Officer Needs Help Urgently
927-D Susp. Circumstances Women District Cars Only (five units
Screaming with shortest ETA to respond)
998 Officer Request Assistance,
Involved In Shooting
999 Officer Needs Help Urgently