You've seen all the cool stuff the OpenNETCF guys are doing, such as the Mobile Ink Library, Desktop Communication Library, Telephony Library and Smart Device Framework,  and if you're interested in participating, Neil Cowburn just announced that OpenNETCF is opening some of these libraries for external participation.

Check it out: http://blog.opennetcf.org/ncowburn/2007/08/14/WantToHelpOutWithAnOpenSourceProject.aspx