CRC handbook is now available online so they can update the latest and greatest fundamental constants with ease. I came across my 1980s-era hardcopy on the bookshelf last week, took it down and leafed through it. There's so much good stuff in there. I like to open it up to random pages and try to figure out what it's about. Often, I'm clueless.
But, I recently came across the heat capacity of water, which reminded me to look up the the heat capacity of air, and I feel a series about kitchen thermodynamics straining to get out.
Hardcopies of older editions of CRC handbooks are easy to find and cheap. Every household should have one on the reference shelf next to a really big dictionary. Sure, you could look up specific words and properties on the internet, but you can't browse serendipitously and learn things you don't really need "right now" the way you can with a book.
It's a rainy day. Curl up with a really big book.
I hot-linked this comic from xkcd. BTW, if the geeks in your life already have hardcopies of the CRC handbook, how about buying them a gift from the xkcd store?