Reading from a file randomly

[NemeziS]

Hello,
I'm writing a jokebot ( more info here: _http://board.univ-angers.fr/thread.php?threadid=3812&boardid=11&styleid=1&sid=1c7d4e37ac995663e49444868a745249 )

I have a little problem of reading blocks of jokes randomly.

Example of my file:

------------------
[COLOR=red][I](start of the first joke block)[/I] [/COLOR] 
Q: What's the Blonde's cheer? 
A: I'm blonde, I'm blonde, 
I'm B.L.O.N....ah, oh well.. 
I'm blonde, I'm blonde, yea yea yea...
[COLOR=red][I](finish of the first joke block)[/I][/COLOR]  
------------------
[COLOR=red][I](start of the second joke block)[/I] [/COLOR]  
Q: Why didn't the blonde want a 
window seat on the plane? 
A: She'd just blow dried her hair 
and she didn't want it blown around too much.
[COLOR=red][I](finish of the second joke block)[/I] [/COLOR] 
------------------
[COLOR=red][I](start of the third joke block)[/I] [/COLOR]  
Q: What did the blonde customer 
say to the buxom waitress 
(reading her nametag) ? 
A: 'Debbie'...that's cute. What 
did you name the other one ?
[COLOR=red][I](finish of the third joke block)[/I] [/COLOR]
------------------

Each joke block is separated from other joke block by ------------------
So I need to read random joke block on command !showjoke.

Thanx for attention.  ;)

Best regards,
NemeziS