Part of the OLPC project's appeal has been its innovative Sugar OS; now Sugar Labs have released a public beta of Sugar on a Stick (SoaS), which allows anybody to create a portable Sugar environment that will run on any computer. Fitting onto a 1GB USB memory stick, SoaS combines a compressed version of Fedora 11 with the Sugar Labs amendments.
There's a known-compatibility list here, out of which the most interesting entry so far is probably the Acer Aspire One netbook listing. The Aspire One is certainly more readily found, either new or second-hand, and so the news that it runs Sugar with no obvious issues is great.
The eventual goal is to be able to give students a working, stable version of their own Sugar environment that they can run on any computer they encounter. It's also a great way for those wanting the child-friendly simplicity of OLPC's software environment on their existing hardware, without spending money on an actual OLPC XO-1 notebook.