Smokeping is a monitoring utility made by the same guy who built mrtg and rrd tool.  Generaly speaking it will ping out and track response times in nice graphs.  It's special sauce (and where it gets its name from) is how it graphs.  As there is more variation in response times, it creates a "fog" on the chart to show where things are not consistent. 

It's actually a lot cooler then that, because its back-end (the actual pinger) can be fanned out, and you can have multiple pinging servers that all report back to a central collector. 

You can also front end this with cacti, so that all your graphs can be presented in one location.  (but you still need to setup the server and pingers.  Cacti just front-ends the graphs.)

Install (centos):

Download and open the smokeping tarball:
gunzip smokeping-2.6.8.tar.gz
tar -xvf smokeping-2.6.8.tar

Install required dependencies
yum install rrdtool-perl.x86_64 fping curl dig mod_fcgid

Install perl modules:
perl -MCPAN -e shell
  install use CGI::Fast FCGI CGI LWP
  install use Config::Grammar Socket6 Net::Telnet Net::OpenSSH

  install use Net::DNS Net::LDAP IO::Socket::SSL Authen::Radius
Or by entering in the following: 
yum install perl perl-Net-Telnet perl-Net-DNS perl-LDAP perl-libwww-perl perl-RadiusPerl perl-IO-Socket-SSL perl-Socket6 perl-CGI-SpeedyCGI

Install the app
./configure --prefix=/opt/smokeping
/usr/bin/gmake install

smokeping then gets deployed into:

Copy the contents of smokepings web stuff into your webserver
mkdir /var/www/html/smokeping
cp -R /opt/smokeping/htdocs/* /var/www/html/smokeping/.


make a copy of the config file, and rename it without an extension
cp /opt/smokeping/etc/config.dist /opt/smokeping/etc/config

then modify it with the following changes:
vim /opt/smokeping/etc/config