I've just added a couple of project proposals related to improving Ext2/Ext3 file system support in the NetBSD Operating System. These are:

• Implement Ext3 file system support
• Improve support for Ext2 root filesystem

If you are interested in getting into file system development — a very interesting research area, believe me! ;-) — this is probably a safe bet. These two projects are not very complex but can quickly benefit NetBSD for different reasons (not only better Linux compatibility). Check out their descriptions for more details!