Yes, today (Tuesday, October 8th) is one of the Fedora 20 Test Days, more specifically, Virtualization Test Day.
Specific information regarding testing Xen on the new Fedora can be found in this Wiki page. For attending and participating, join us now on IRC at #fedora-test-day (Freenode)!
Fedora 20 will be one of the first mainstream distros shipping Xen 4.3, so come and help us making sure it will work great for you and all Fedora users!!