If you’re looking for a weekend project, having a go at the latest Ubuntu
(beta) release would be a fun one. Ubuntu 12.04 Precise Pangolin, a long-term support (LTS) release, is now in beta and available for download from Canonical
Being an LTS release, there aren’t a lot of earth-shattering changes, but Canonical has definitely tweaked things a bit. New features include making Rhythmbox (which includes access to the Ubuntu One Music Store) the default music player, an update to LibreOffice (v.3.5), some minor interface improvements, increased support for ClickPad devices (where a physical button is built into a trackpad), and more.
Overall, version 12.04 looks a lot like version 11.10, which is to say that it’s simple and beautiful. Do yourself and the open source community a favor and take it for a spin.