If you’re interested in looking at the Sugar desktop and some of the Activities which are on the OLPC X0-1, then James Munro, a student here, has been working over the summer on a related project and produced a LiveCD of Xubuntu which boots directly into Sugar with a selection of Activities to try. You can read more about the project and download the LiveCD on our wiki. Without an X0-1 of your own, this is probably the easiest way to try out the Sugar desktop right now. Any comments, questions or problems, do get in touch with me or James via our blogs. Thanks!
Note: The LiveCD is still being tested. It’ll be available via the wiki soon.