How do you guys measure temps w/o environment monitors?

[The Raven]

Hey guys, I was just wondering how you measure temps on boards and/or peripherals that don't have temp monitors on them. I've been pokin' around w/ a handheld and want to be able to check out my temps with the case closed. Is there a product that can be installed that will measure temps for all my components? And if so which ones are the best? Thanks.