RECIPE 1
--------
Set DND (Do not disturb) from your dialplan and 
reflect the status on FOP:

# Example on setting DND state from the dialplan
# *78 Sets DND ON
# *79 Sets DND OFF
#
# This example only sets the dnd db value and
# signals FOP to display the status on the button
# you might have to add a check in your stdexten
# macro to honour the DND status

in extensions.conf:

exten => *78,1,Set(DB(dnd/${CUT(CHANNEL|-|1)})=Break)
exten => *78,n,UserEvent(ASTDB|Channel: ${CHANNEL}^Family: dnd^Value: Break)
exten => *78,n,Hangup

exten => *79,1,Set(DB(dnd/${CUT(CHANNEL|-|1)})=)
exten => *79,n,UserEvent(ASTDB|Channel: ${CHANNEL}^Family: dnd^Value: ^)
exten => *79,n,Hangup

in op_astdb.cfg:

[dnd]
settext=DND: ${value}|
fopledcolor=0x001020^0|0x00A000^0

in op_buttons.cfg

[SIP/1234]
..
astdbkey=SIP/1234

RECIPE 2
--------
How to monitor rxfax. This is just a barebones sample, you can 
customize it for your needs. You have to Goto to the fax context
from your dialplan:

in extensions.conf:

exten => fax,1,Goto(rxfax,s,1)

[rxfax]
exten => s,1,Set(FAXFILE=/var/spool/fax/fax-${TIMESTAMP}.tif)
exten => s,2,Set(LOCALSTATIONID=My Company)
exten => s,3,UserEvent(Newexten|Channel: FAX/FAX-${UNIQUEID}^State: Up^Uniqueid: 1234)
exten => s,4,rxfax(${FAXFILE})
exten => s,5,Hangup()
exten => t,1,Hangup()
exten => h,1,UserEvent(Hangup|Channel: FAX/FAX-${UNIQUEID}^State: Down^Uniqueid: 1234)

in op_buttons.cfg:
[FAX/FAX]
Position=1
Label="Fax"



RECIPE 3
--------
How to monitor voicemailmain (users entering the voicemail application)
You have to define a regular extensions that performs a 'Goto' to the
vmail context (similar to the fax case above)

in extensions.conf:

[vmail]
exten => s,1,SetLanguage(es)
exten => s,2,UserEvent(Newexten|Channel: VMAIL/VMAIL-${UNIQUEID}^State: Up^Uniqueid: 4321)
exten => s,3,VoicemailMain(${CALLERIDNUM}@internos)
exten => t,1,Hangup
exten => h,1,NoOp(Hangup en voicemail)
exten => h,2,UserEvent(Hangup|Channel: VMAIL/VMAIL-${UNIQUEID}^State: Down^Uniqueid: 4321)
exten => h,3,Hangup

in op_buttons.cfg:

[VMAIL/VMAIL]
Position=1
Label="Voicemail"

RECIPE 4
--------
Show day/night mode based on an asterisk db value:

in extensions.conf:

exten => 80,1,DBPut(daymode/DAYMODE=Day);
exten => 80,2,UserEvent(ASTDB|Family: daymode^Channel: daymode^Value: Day)
exten => 80,3,Hangup
;
exten => 81,1,DBPut(daymode/DAYMODE=Night);
exten => 81,2,UserEvent(ASTDB|Family: daymode^Channel: daymode^Value: Night)
exten => 81,3,Hangup

in op_astdb.cfg:

[daymode]
setlabel=${value}