Mine

[custom-chag]
exten => s,1,Noop(Checking to see if today is a chag)
exten => s,n,Set(chag=not_set)
exten => s,n,AGI(jh.php)
exten => s,n,Noop(chag is set to ${chag})
exten => s,n,Gotoif($[${chag}=chag]?chag|1:nochag|1)

exten => chag,1,Noop(Today is a Chag)
exten => chag,n,Playback(xmas-lights)
exten => chag,n,Hangup

exten => nochag,1,Noop(Today is NOT a chag)
exten => nochag,n,Playback(our-business-hours-are)
exten => nochag,n,Hangup