Here's sudoers sample taken from FreeBSD Handbook, hope it helps.
##
## Sample /etc/sudoers file.
##
## This file MUST be edited with the 'visudo' command as root.
##
## See the sudoers man page for the details on how to write a sudoers file.
##
#
###
## User alias specification
###
#User_Alias FULLTIMERS = millert, mikef, dowdy
#User_Alias PARTTIMERS = bostley, jwfox, crawl
#User_Alias WEBMASTERS = will, wendy, wim
#
###
## Runas alias specification
###
#Runas_Alias OP = root, operator
#Runas_Alias DB = oracle, sybase
#
###
## Host alias specification
###
#Host_Alias SPARC = bigtime, eclipse, moet, anchor:\
# SGI = grolsch, dandelion, black:\
# ALPHA = widget, thalamus, foobar:\
# HPPA = boa, nag, python
#Host_Alias CUNETS = 128.138.0.0/255.255.0.0
#Host_Alias CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0
#Host_Alias SERVERS = master, mail, www, ns
#Host_Alias CDROM = orion, perseus, hercules
#
###
## Cmnd alias specification
###
#Cmnd_Alias DUMPS = /usr/sbin/dump, /usr/sbin/rdump, /usr/sbin/restore, \
# /usr/sbin/rrestore, /usr/bin/mt
#Cmnd_Alias KILL = /usr/bin/kill
#Cmnd_Alias PRINTING = /usr/sbin/lpc, /usr/bin/lprm
#Cmnd_Alias SHUTDOWN = /usr/sbin/shutdown
#Cmnd_Alias HALT = /usr/sbin/halt, /usr/sbin/fasthalt
#Cmnd_Alias REBOOT = /usr/sbin/reboot, /usr/sbin/fastboot
#Cmnd_Alias SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh, \
# /usr/local/bin/tcsh, /usr/bin/rsh, \
# /usr/local/bin/zsh
#Cmnd_Alias SU = /usr/bin/su
#Cmnd_Alias VIPW = /usr/sbin/vipw, /usr/bin/passwd, /usr/bin/chsh, \
# /usr/bin/chfn
#
###
## Override builtin defaults
###
#Defaults syslog=auth
#Defaults:FULLTIMERS !lecture
#Defaults:millert !authenticate
#Defaults@SERVERS log_year, logfile=/var/log/sudo.log
#
###
## User specification
###
#
## root and users in group wheel can run anything on any machine as any user
#root ALL = (ALL) ALL
#%wheel ALL = (ALL) ALL
#
## full time sysadmins can run anything on any machine without a password
#FULLTIMERS ALL = NOPASSWD: ALL
#
## part time sysadmins may run anything but need a password
#PARTTIMERS ALL = ALL
#
## jack may run anything on machines in CSNETS
#jack CSNETS = ALL
#
## lisa may run any command on any host in CUNETS (a class B network)
#lisa CUNETS = ALL
#
## operator may run maintenance commands and anything in /usr/oper/bin/
#operator ALL = DUMPS, KILL, PRINTING, SHUTDOWN, HALT, REBOOT,\
# /usr/oper/bin/
#
## joe may su only to operator
#joe ALL = /usr/bin/su operator
#
## pete may change passwords for anyone but root on the hp snakes
#pete HPPA = /usr/bin/passwd [A-z]*, !/usr/bin/passwd root
#
## bob may run anything on the sparc and sgi machines as any user
## listed in the Runas_Alias "OP" (ie: root and operator)
#bob SPARC = (OP) ALL : SGI = (OP) ALL
#
## jim may run anything on machines in the biglab netgroup
#jim +biglab = ALL
#
## users in the secretaries netgroup need to help manage the printers
## as well as add and remove users
#+secretaries ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser
#
## fred can run commands as oracle or sybase without a password
#fred ALL = (DB) NOPASSWD: ALL
#
## on the alphas, john may su to anyone but root and flags are not allowed
#john ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root*
#
## jen can run anything on all machines except the ones
## in the "SERVERS" Host_Alias
#jen ALL, !SERVERS = ALL
#
## jill can run any commands in the directory /usr/bin/, except for
## those in the SU and SHELLS aliases.
#jill SERVERS = /usr/bin/, !SU, !SHELLS
#
## steve can run any command in the directory /usr/local/op_commands/
## as user operator.
#steve CSNETS = (operator) /usr/local/op_commands/
#
## matt needs to be able to kill things on his workstation when
## they get hung.
#matt valkyrie = KILL
#
## users in the WEBMASTERS User_Alias (will, wendy, and wim)
## may run any command as user www (which owns the web pages)
## or simply su to
www.
#WEBMASTERS www = (www) ALL, (root) /usr/bin/su www
#
## anyone can mount/unmount a cd-rom on the machines in the CDROM alias
#ALL CDROM = NOPASSWD: /sbin/umount /CDROM,\
# /sbin/mount -o nosuid\,nodev /dev/cd0a /CDROM