From Gman:

Charisma Carpenter and Alyson Hannigan were reunited on the November
30 episode of Veronica Mars.

This is an opportunity to let UPN know via e-mail how much you enjoyed
seeing these Buffy regulars on VM. You could also mention that you
would like to see more Buffy and Angel regulars on UPN in a Joss
Whedon-produced Buffy/Angel spin-off.

Go to www.upn.com and click on "Contact Us" to send an e-mail to UPN.
It's quick and it's free. A great combination (like Charisma & Alyson.

If you missed tonight's episode, check to see if UPN rebroadcasts
Veronica Mars in your market. In the New York/New Jersey area the
Wednesday episode is rebroadcast on Sunday at 7:00 PM. Alyson and
Charisma were terrific together and are not to be missed.