Suppose I have many SNMP enabled devices (Switched Rack PDU, etc).
I have configured user macros {$COMMUNITY}, {$PDUOUTLETNUMBER} at the global,template,host levels and I would like to perform an action from zabbix map using a GUI script.

Universal script command would be:
/usr/local/bin/snmpset -c {$COMMUNITY} -v 1

PowerNet-MIB::rPDUOutletControlOutletCommand.{$PDUOUTLETNUMBER} i 3 2>&1

http://www.zabbix.com/documentation/2.0/manual/appendix/macros/supported_by_location

Unfortunately user macros do not supported in GUI scripts, so I have no way