It's fun to make stuff work.
I just verified that with current Cooker, I can synchronize a bunch of contacts from a Blackberry (Curve) to a Windows Mobile device (HTC Apache, running WM 6.1) and it all works. Phone numbers, email addresses, everything shows up right.
Sure, this all relies on a messy hack to Barry's opensync plugin, but hey, it works, and you don't need to know that.
Also fun lately - Cooker is booting like greased lightning, thanks to quite a lot of bug fixes and Fred Crozat's work on readahead / preload. Fastest I can remember it booting for years. Neat stuff.