I've posted before about Damn Small Linux, since I discovered it as my gateway into the world of Linux computing - it rejuvenated my girlfriend's tired ol Windows laptop.
Well it has now passed the version 1.0 stage, and is available in multiple formats as a way to try out Linux cheaply and cheerfully. Coolest of all, for those new to 'The Revolution (TM)', if you download the embedded .zip file version, you can run it direct from Windows using QEMU (included with the zip). Geekgasm!
There's now no excuse not to try out Linux. Oh, except that it runs very slow under QEMU, unless you've got a fast processor (over 1.5 Ghz). But then there's the USB-key version, the CD-version, the business-card version, and all sorts of other goodness.
You can find the downloads pagehere.