The PaleyFest fun won't stop! Jon Hamm  and his hilarious Mad Men costars attended The Paley Center For Media's annual celebration of cast members and creators in LA on Friday, and they brought on the laughs during a panel discussion about their characters. In between all the jokes, Jon, Vincent Kartheiser, Elisabeth Moss , and their castmates opened up about how they're already mourning the end of their show . In other memorable festival moments, Orange Is the New Black ladies Taylor Schilling and Laura Prepon showed us how they let loose when they're not filming prison scenes, and Kristen Bell  laughed so hard she had to cover her mouth while dishing details about Veronica Mars. Meanwhile, Neil Patrick Harris  went shirtless  on Skype during a panel about How I Met Your Mother, and the Pretty Little Liars cast put the drama on hold as they hung out at their event. Keep reading to see all the excitement unfold, and check back later for more photos as the celebration continues!
Jon Hamm  and Vincent Kartheiser showed a goofy side we'd never see on Mad Men.
Vincent Kartheiser and Elisabeth Moss  sat near Christina  Hendricks and Robert Morse.
Elisabeth Moss  wore a formfitting black-and-white dress.
Christina  Hendricks wore a green ensemble.
Kiernan Shipka linked up with her onscreen dad.
The cast posed for a group photo with Mad Men creator Matthew Weiner.
Kristen Bell  lit up during a chat about Veronica Mars.
Taryn Manning and Jason Biggs joined their Orange Is the New Black costars on stage.
Neil Patrick Harris 's shirtless  antics made up for his absence.
Lucy Hale wore a patterned ensemble.
Judd Apatow received the festival's icon award on Monday. His wife Leslie Mann and daughter Iris were his dates.
Jason Dohring sat next to a giggly Kristen Bell .
Alyson Hannigan wore a white dress for the festivities.
Josh Radnor  and Cristin Milioti sat next to each other at the How I Met Your Mother event.
Uzo Aduba struck a pose before the Orange Is the New Black panel.
The cast of How I Met Your Mother reflected on filming the last season of their show.
The ladies of Pretty Little Liars — Ashley Benson, Shay Mitchell, Lucy Hale, Troian Bellisario, and Sasha Pieterse — huddled for a group photo.
Ian Harding posed for a solo photo without his Pretty Little Liars castmates.
Cobie Smulders wore her hair up.
Keegan Allen slicked his hair back for the Pretty Little Liars event.
Ashley Benson wore a sophisticated top and matching skirt.
Cobie Smulders let out a big laugh and leaned into How I Met Your Mother costar Alyson Hannigan.