here's another one :)
alias randnick {
while ($nick($chan,$rand(1,$nick($chan,0))) != $me) var %temp = $v1
return %temp

That way it's shorter but doesnt mean your way is all that bad. It's clearer for example.
But. %temp is global, that isnt good. Use var. Also, even though goto-loops are there, it's cooler to leave them alone.

I forgot the closing bracket of randnick..

aaaaaaaw, im so proud of you SonicX! <3

Maybe just a minor detail... but did anyone consider what happens if its only you in the channel.

I know its a rare thing but maybe, I should have something that works. Its quite old and uses goto and such ;). But it works...

-----

alias randnick {
var %chan = $iif($1,$1,$chan)
if ($chan(%chan).status == joined) {
if ($nick(%chan,0) > 1) {
var %temp
:retry
%temp = $nick(%chan,$rand(1,$nick(%chan,0)))
if (%temp == $me && %temp) { goto retry }
return %temp
}
else {
echo $color(info) -s * $ $+ randnick: Error only one person on %chan
halt
}
}
else {
echo $color(info) -s * $ $+ randnick: You're currently not in %chan
halt
}
}

-----------

Uhm yes as you can see this allows normal $randnick or $randnick(#channel). It checks if you joined the channel or not. And ofcourse checks if there are more then just you in there.
If you don't want it to halt the script on an error you could remove the halt commands and thats fixed.