Blackberry Secret Codes and Hacks

Blackberry secret codes for hidden menus work a bit differently to all other manufacturers since you don't use the *#code# sequence but rather activate most of the codes by holding the ALT key. As always it is right to point out that these are not some magic Blackberry hacks just the codes to access the hidden menu systems which people commonly refer to as the Blackberry secret codes. To use these codes you just have to enter the key sequence as specified.
Blackberry secret codes and hacks
Hidden Functions (HOLD ALT)
CodeFunction
ALT+NMLLChanges the signal meter from the standard bars to a decibel display, entering the code again will revert back to the bars
ALT+LSHIFT+HThe Techinical information menu, if you are trying to get support or help you will probably need the information displayed here
ALT+VALDValidates the address book, can only be used in the address book
ALT+RBLDForces the address book to rebuild, can only be used in the address book
*#06#Displays the IMEI (home screen)
ALT+RBVSUsed in the browser to view the page source code, useful if you are developing applications
ALT+LGLGDisplays the devices event log, if you are struggling to get BES/BIS working the information here can be very useful
ALT+SHIFT+DELSoft reset a blackberry device, this is not a format or hard reset. Just a reboot
Smart System Codes (Type these in a message box for example while composing a new e-mail)
CodeFunction
MYVERDisplays the Software Version and Model Number of the device
LDLocal Date is displayed
LTLocal Time is displayed
MYSIQDisplays the device owner information
MYPINDevice PIN is displayed
Other Codes
CodeFunction
ALT+LEFTCAPSDisplays the Language Selection Screen
LOLOUse on the Date/Time screen to display the network date and time
ALT+VIEWDisplays the ID's in the messages menu
ALT+THMNUse in the themes menu to disable themes
ALT+THMDUse in the theme menu to return to the default blackberry theme
ALT+SMONEnables the simulated WLAN wizard (WLAN Menu)
ALT+SMOFDisables the simulated WLAN wizard (WLAN Menu)
BUYRDisplay data and voice usage, enter at the status screen (options>status)
TESTPerforms a full device test, enter at the status screen (options>status)
Sim Card Shortcuts (no ALT required, found under Options>Advanced>Sim Card)
CodeFunction
MEP1Enable/Disable Sim personalization
MEP2Enable/Disable Network personalization
MEP3Enable/Disable Network subset personalization
MEP4Enable/Disable Service provider personalization
MEP5Enable/Disable Corporate personalization
MEPDMEP Information Display - Shows Status
A lot of the Blackberry Secret codes are actually shortcuts to the hidden menu areas that people are simply not aware of.