[mainmenu]
  exten => s,1,Answer
  exten => s,2,SetMusicOnHold(default)
  exten => s,3,DigitTimeout,5
  exten => s,4,ResponseTimeout,10
  ;SAI menu - 1 for tech support, 2 for voicemail, 3 for echo test
  exten => s,5,Background(sai-welcome)
  exten => s,6,Background(sai-choose)

  ; Tech Support
  exten => 1,1,AGI(dima-test.agi)
  exten => 1,2,SetGlobalVar(ACCOUNTCODE=${callerid})
  exten => 1,3,SetVar(testcallerid=${callerid})
  exten => 1,4,Background(sai-reptech-welcome)
  exten => 1,5,Queue(rep-tech)

  ; Leave Voicemail
  exten => 2,1,VoicemailMain()
  exten => 2,2,Hangup

  ; Echo Test
  exten => 3,1,Playback(demo-echotest)
  exten => 3,2,Echo
  exten => 3,3,Playback(demo-echodone)
  exten => 3,4,Goto(mainmenu,s,6)

  ; EAGI Test
  exten => 4,1,Answer()
  exten => 4,2,Wait(1)
  exten => 4,3,AGI(sai-repid.agi)
  exten => 4,4,Wait(1)
  exten => 4,5,Hangup

  ; Play Music-on-Hold
  exten => 5,1,MusicOnHold(default)
  exten => 5,2,Goto(mainmenu,s,6)
  ; #=hangup
  exten => #,1,Playback(sai-thanks)
  exten => #,2,Hangup

  exten => t,1,Goto(#,1)         ; If they take too long, give up
  exten => i,1,Playback(invalid) ; "That's not valid, try again"

 [default]
  include => mainmenu
  include => local
  include => longdistance
  include => joe-iax
  include => npi-iax

  ; Record voice file to /tmp directory
  exten => 205,1,Wait(2) ; Call 205 to Record new Sound Files
  exten => 205,2,Record(/tmp/asterisk-recording:gsm) ; Press # to stop recording
  exten => 205,3,Wait(2)
  exten => 205,4,Playback(/tmp/asterisk-recording) ; Listen to your voice
  exten => 205,5,wait(2)
  exten => 205,6,Hangup


Example menu with timeout and invalid option. Works with Asterisk 1.6 

exten => s,1,Set(NUMINVALID=0)
exten => s,2,Set(NUMTIMEOUTS=0)
exten => s,3,Background(thank-you-for-calling)
exten => s,4,Set(TIMEOUT(digit)=5)
exten => s,5,Set(TIMEOUT(response)=10)
exten => s,6,WaitExten(5)

exten => t,1,Set(NUMTIMEOUTS=$[${NUMTIMEOUTS}+1]})
exten => t,2,Gotoif($["${NUMTIMEOUTS}" < "3"]?s,3)
exten => t,3,Background(vm-goodbye)
exten => t,4,Hangup()

exten => i,1,Set(NUMINVALID=$[${NUMINVALID}+1]})
exten => i,2,Gotoif($["${NUMINVALID}" < "4"]?:10)
exten => i,3,Background(invalid)
exten => i,4,Goto(s,3)
exten => i,10,Playback(vm-goodbye)
exten => i,11,Hangup()

[transit-ivr]
 exten => s,1,Answer
 exten => s,2,SetVar(ivrflag=transit)                                                    ; Unused at the moment
 exten => s,3,Background(transit-ivr/grtg-3)                                             ; Play the initial greeting (interruptable)
 exten => s,4,Goto(transit-ivrmain,s,1)                                                  ; Start the menuing system after the message completes

 exten => _x,1,Goto(transit-ivrmain,s,1)                                                 ; Start the menuing system if the user presses any key during the greeting

[transit-ivrmain]
 exten => s,1,NoOp(s,1 - Has ${digitstack} in the digitstack)
 exten => s,2,GotoIf($[${LEN(${digitstack})} = 0]?s-restart,1)                ; If there is nothing in the stack at all then restart the stack 
 exten => s,3,System(/var/lib/asterisk/sounds/transit-ivr/filexists /var/lib/asterisk/sounds/transit-ivr/${digitstack}.gsm)  ; test for the existance of this path as a recording
 exten => s,4,Background(transit-ivr/${digitstack})
 exten => s,5,NoOp()                                                                     ; insert padding to offset s,9 so it in turn is offset cleanly enough for it's n+101 jump
 exten => s,6,NoOp()
 exten => s,7,NoOp()
 exten => s,8,NoOp()
 exten => s,9,System(/var/lib/asterisk/sounds/transit-ivr/filexists /var/lib/asterisk/sounds/transit-ivr/${digitstack}?.gsm)  ; test for the existance of additional recordings underneath the current path

 exten => s,104,NoOp(we should warn the user they chose an invalid option...)                         ; Relative to s,3
 exten => s,105,SetVar(digitstack=${digitstack:0:$[${LEN(${digitstack})} - 1]})
 exten => s,106,Goto(s,1)

 exten => s,110,NoOp(there aren't any menus below this one, so go back up one level)     ; Relative to s,9
 exten => s,111,SetVar(digitstack=${digitstack:0:$[${LEN(${digitstack})} - 1]})
 exten => s,112,Goto(s,1)

 exten => s-restart,1,SetVar(digitstack=0)
 exten => s-restart,2,Goto(s,1)

 ; Capture keypresses
 exten => _X,1,SetVar(digitstack=${digitstack}${EXTEN})
 exten => _X,2,GotoIf($[${digitstack:$[${LEN(${digitstack})} - 1],1} = 8]?_X,10)
 exten => _X,3,Goto(s,1)
 exten => _X,10,SetVar(digitstack=${digitstack:0:$[${LEN(${digitstack})} - 2]})          ; Eight pops two digit off the stack... (including the 8 itself)
 exten => _X,11,Goto(s,1)

 #!/bin/bash
 #  Test for the existance of files based on shell globbing patterns

 for a in $1;
 do
  if [ -f $a ] ; then
        # there are one or more files that match;
        exit;
  else
        # there aren't any files that match;
        exit 1;
 fi;
done;

 8192 Aug 27 00:53   .
 20480 Aug 27 00:53  ..
 54285 Aug 25 22:46  0.gsm                  This is the root menu
 66429 Aug 25 22:47  01.gsm                This is menu 1 off of the root
 17556 Aug 25 22:46  02.gsm                This is menu 2 off of the root
 17292 Aug 25 22:44  023.gsm               This is informational recording 3 off of menu 2 off of the root
 115533 Aug 25 22:48 03.gsm                This is menu 3 off the root
 {and so on...}

 [deeper]
exten => s,1,Background(demo-nomatch)
;exten => s,1,AGI(festival-script.pl|"deeper menu")
exten => s,2,Goto,options|s|1

[options]
exten => s,1,Background(demo-instruct)
;exten => s,1,AGI(festival-script.pl|"options menu")
exten => 1,1,Goto,deeper|s|1
exten => 2,1,Goto,sales|s|1

[sales]
exten => s,1,Background(demo-thanks)
;exten => s,1,AGI(festival-script.pl|"sales menu")
exten => 0,1,Goto,from-sip|1000
exten => 1,1,Goto,Menu|s|1

[Menu]
exten => s,1,Background(demo-congrats)
;exten => s,1,AGI(festival-script.pl|"menu menu")
exten => 1,1,Goto,sales|s|1
exten => 2,1,Goto,options|s|1
exten => i,1,Goto,s
exten => t,1,Goto,s


;The specific method to enter the menu is up to you but I used my sip phone to test.
[from-sip]

exten => 100,1,Answer
exten => 100,2,Goto,Menu|s|1

[Menu]
exten => s,1,Background(demo-congrats)
exten => 1,1,Goto,sales|s|1
exten => 2,1,Goto,options|s|1  

;tested with Asterisk 1.6.2.5

[macro-mymenu_addlevel]
exten = s,1,NoOp(${MACRO_CONTEXT})
exten = s,2,Set(Count=${FIELDQTY(CUR_LEVEL,#)})
exten = s,n,Gotoif($[ "${CUT(CUR_LEVEL,#,$[${Count}])}" = "${MACRO_CONTEXT}" ] ]?s-exit) ;if last level in stack same as current context then exit.
exten = s,n,Set(PREV_LEVEL=${CUR_LEVEL})
exten = s,n,Set(__CUR_LEVEL=${IF($[ "${PREV_LEVEL}" != "" ]?${PREV_LEVEL}#:${PREV_LEVEL})}${MACRO_CONTEXT}); add MACRO_CONTEXT to stack
exten = s,n(s-exit),NoOp(Exit form macro-mymenu_addlevel)

[macro-mymenu_prevlevel]
exten = s,1,Set(Count=${FIELDQTY(CUR_LEVEL,#)})
exten = s,2,Set(TMP=${CUR_LEVEL})
exten = s,n,Set(TOGO=${CUT(TMP,#,$[${Count}-1])});Count alwayse >0
exten = s,n,Set(__CUR_LEVEL=${IF( $[${Count}>1]?${CUT(TMP,#,-$[${Count}-2])}:"")}); if count>1 set CUR_LEVEL, else clear it.
exten = s,n,NoOp(${CUR_LEVEL})
exten = s,n,Goto(${TOGO},s,1)

[voicemenu-mymenu_level0]
exten = s,1,Macro(mymenu_addlevel)
exten = s,n,Answer()
exten = s,n,Set(TIMEOUT(digit)=5)
exten = s,n,Set(TIMEOUT(response)=10)
exten = s,n,Background(greatings_1)
exten = s,n,WaitExten(5)
exten = 0,1,Dial(SIP/6051,300,r); fax
exten = 1,1,Goto(voicemenu-mysubmenu1_level1,s,1)
exten = 2,1,Goto(voicemenu-mysubmenu2_level1,s,1)
exten = i,1,Goto(s,1)
exten = t,1,Goto(voicemenu-mymenu-operator,s,1)

[voicemenu-mysubmenu1_level1]
exten = s,1,Macro(mymenu_addlevel)
exten = s,n,Background(payment_1)
exten = s,n,WaitExten(5)
exten = 0,1,Goto(voicemenu-mymenu-operator,s,1)
exten = 1,1,Goto(voicemenu-mysubmenu3_level2,s,1)
exten = *,1,Macro(mymenu_prevlevel)
exten = i,1,Goto(s,1)
exten = t,1,Goto(voicemenu-mymenu-operator,s,1)

[voicemenu-mysubmenu2_level1]
exten = s,1,Macro(mymenu_addlevel)
exten = s,n,Background(payment_2)
exten = s,n,WaitExten(5)
exten = 0,1,Goto(voicemenu-mymenu-operator2,s,1)
exten = 1,1,Goto(voicemenu-mysubmenu3_level2,s,1)
exten = *,1,Macro(mymenu_prevlevel)
exten = i,1,Goto(s,1)
exten = t,1,Goto(voicemenu-mymenu-operator2,s,1)

[voicemenu-mysubmenu3_level2]
exten = s,1,Macro(mymenu_addlevel)
exten = s,n,Background(howtodosomething)
exten = s,n,WaitExten(5)
exten = *,1,Macro(mymenu_prevlevel)
exten = i,1,Goto(s,1)
exten = t,1,Goto(voicemenu-mymenu-operator1,s,1)