Nothing original here, but this is a great tip, so I want to share it. Thanks to @thegrugq for cluing me into this via Twitter.
For everyone running OS X 10.7 or 10.8 on their Macs (and really, EVERYONE should be on 10.8; the security benefits are non-trivial) and are using FileVault 2 to encrypt your filesystems (you are, right?) here's a good tip I picked up the other day:
$ sudo pmset -a destroyfvkeyonstandby 1
$ sudo pmset -a hibernatemode 25
This has the effect of destroying the memory-resident FileVault encryption key, writing the contents of memory to disk, and removing power from RAM (i.e., hibernating). Doing this will help protect your laptop from getting raped via FireWire DMA by your hotel's cleaning staff or by the Border Patrol.
A nice article on the topic:
Tips via The Grugq: