Requires JoeyCMDs
http://addons.eventscripts.com/addons/view/JoeyCMDs

Attention!ª! To use JoeyCMDs you just install it you dont need to add it in autoexec.cfg!

Credits
Special thanks to SuperDave has always.
Errant and Don help ;)

It's just a simple !spec !unspec.
This script has amazing has it seems it's the only one available has stand-alone that I know of.

CVARS

Add to you server.cfg

all_users 1 //(if everyone can use it or just admins)

spec_killed 0 //(if for same reason you are killed when say !spec or !unspec this keeps your score safe)

spec_deathmatch 1 //(instant respawn or wait end round)