Depends on your OS... I use Speedfan on my Windows laptop to monitor the CPU temp because my internal cooling fan failed. On my desktop, I'm running Ubuntu (Linux), so I use something called sensors-applet, which just shows my temps in a notification area on my lower taskbar...I like it because it allows me to set maximum/minimum temps for any component that has a thermal sensor, as well as showing fan speeds and voltages connected to the motherboard. But, this is on a Linux machine, so your possibilities may vary.
Once upon a midnight dreary, while I pron surfed, weak and weary, over many a strange and spurious site of ' hot XXX galore'. While I clicked my fav'rite bookmark, suddenly there came a warning, and my heart was filled with mourning, mourning for my dear amour, " 'Tis not possible!", I muttered, "give me back my free hardcore!"... quoth the server, 404.